FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Ratbird on May 28, 2014, 09:51:21 AM
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A couple of years ago I bought a 9 inch open differential (3.89) from a very knowledgeable guy who specializes in rear ends. It was out of an 1968 F-100 and was supposed to be an "open rear end. (It was just to get me rolling)
This past weekend I wanted to video it doing a burnout. After the burnout I went back and looked at the tracks, to my surprise both tires were spinning. I had about 100 foot long two tire burnout. Is that possible with an open rear end? I was told that power goes to the wheel that is spinning, or does not have good traction.
The reason I ask, and the reason I did the burnout, was because I am getting ready to buy a 4.11 trac loc 3rd member and I wanted to compare traction.
thx, Dave
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Sounds like it does have some kind of traction lock unit in it. You can tell for sure by jacking up the back of the vehicle and rotating one of the rear tires by hand. If it is an open rear end, the other rear tire will spin in the opposite direction. If it has some kind of positraction or traction lock setup, both tires will rotate in the same direction.
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Well, I've never heard of anything like that happening with an "open" rearend, especially if you laid it down for 100 feet. In fact, I'd like one of those myself :), the price would be right. Jay has the quick check that doesn't fail, do you remember what the internals looked like?
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Yep, you lucked out as no way would an open rear burn both tires, let alone 100' :)
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If I jack it up and turn a tire by hand the other side turns in the opposite direction, thus an open differential.
In the burnout the car even started to slide sideways with the slope of the road. Here's the only pictures that I have. The differential picture of the pumpkin on the little floor jack is probably the best. It's about 2/3's the way down.
https://plus.google.com/photos/101492851059660555641/albums/5796586478747315697?banner=pwa&authkey=CJSKjNbR6eunsgE
Sure is weird, wish I would have taken a picture of the burnout tracks. BTW, I had on stock street tires when I did the burnout, not the cheater slicks in the pictures.
thx, Dave J
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Maby someone made one to many one Wheel
burnouts and welded the spidergears to the
axle in the differetial
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True on the failed spiders. Still, very odd that it's not a OEM Ford Traction Lock (a.k.a. Trak-Lok) as I've also never seen an open rear end spin both tires. Could also have a poor man's mini-spool with welded gears (welded on purpose) but it would still spin both the same way. Very strange!
http://www.fourwheeler.com/how-to/transmission-drivetrain/131-0901-welding-spider-gears-locking-differential-4wd/
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Agreed, very strange.
I'm going home in an hour and will try it again.
Stay tuned.........
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Well holy shiitake sauce, it must be a trac-lok. I just laid down two 70 - 80 foot burnouts and got the skid pictures to show it. Not only that, but I jacked up the rearend and turned either wheel and the opposite wheel did NOT turn.
I positively remember turning one and the other rotating the opposite way before. However, that must have been before I put in the 3.89. So the guy who sold me the current pumpkin was mistaken and he sold me a trac-lok. That would explain a lot of things. For one, the old 390 felt powerful enough, but it would barely spin the cheater slicks, which at the time I thought was a one wheel wonder. That was because the clutch was stock, and the rear end was a trac-lok.
Man, I'm sorry to have bothered everyone with yet another rookie mistake.
I'm guessing that, because the one wheel will turn (while jacked up and out of gear) and the other doesn't reverse, then I must have the clutch type thingy in there - would that be correct?
Dave J
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Even with a Traction Lock (clutches) the wheels still turn together when jacked up. I have sometimes seen open wheelers lay two stripes, but not consistently.
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Well holy shiitake sauce, it must be a trac-lok. I just laid down two 70 - 80 foot burnouts and got the skid pictures to show it. Not only that, but I jacked up the rearend and turned either wheel and the opposite wheel did NOT turn.
I positively remember turning one and the other rotating the opposite way before. However, that must have been before I put in the 3.89. So the guy who sold me the current pumpkin was mistaken and he sold me a trac-lok. That would explain a lot of things. For one, the old 390 felt powerful enough, but it would barely spin the cheater slicks, which at the time I thought was a one wheel wonder. That was because the clutch was stock, and the rear end was a trac-lok.
Man, I'm sorry to have bothered everyone with yet another rookie mistake.
I'm guessing that, because the one wheel will turn (while jacked up and out of gear) and the other doesn't reverse, then I must have the clutch type thingy in there - would that be correct?
Dave J
If one wheel turns, but the other does NOT turn, when you jack it up, and when you hammer it both wheels spin equally, sounds like a Detroit Locker to me. That would be the ultimate score. Does it make a ratcheting sound during low speed turns when you're off the gas? Does it squeal the inside tire during turns when you're giving it even light amounts of pedal?
I have heard of 4 pinion open differentials being shimmed to tighten the spider gears to make a 'poor man's' limited slip, but if that was the case, the other wheel would turn the opposite direction when you spun one side, like any other open dif. If both tires spin the same direction, that would tell me clutch type limited slip.
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Hm, well I don't know what to make of it now. I'll try to upload the video and the pictures tomorrow evening.
The guy that sold me this is what I would call an expert. This is his main work, and he has a lot of years experience. I was told by more than one person that he is one of two guys in Albuquerque that can really build precision, quality, diffs.
I'll try to contact him tomorrow and see what he thinks. He has a trak-lok 4.11 he will trade me for mine and $400. It's not rebuilt, but he said it's in good shape. He said it'll be a little loud, but with my Ratbird I won't be able to hear a thing.
I know mine's not a locker because I've done some 4 wheeling in the mountains, and hauling firewood. I've been in my truck when I hit pavement and forgot to unlock the hubs - thus, I know how they bind and bite when cornering.
Stay tuned again!
Thx to everyone again.
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The 4 pinion diff under my Mustang would spin both tires 50ft or so.
In neutral both rears turned the same way , but holding drive shaft opposite.
Trac Loc turns one wheel if drive shaft is held.
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When I jacked it up and turned the drivers side wheel, the passengers side wheel started to turn in the opposite direction for about 1/4 of a turn - then it stopped. The drive shaft was turning. Then I turned the passengers side and the drivers side did nothing. Went back to the drivers side and turned it and the passengers side did nothing. Each time the drive shaft was always turning.
I'll call the guy who sold me it and see what he says. Might be today, but most likely this evening.
thx, Dave J
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Careful...he might ask for it back!
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When I jacked it up and turned the drivers side wheel, the passengers side wheel started to turn in the opposite direction for about 1/4 of a turn - then it stopped. The drive shaft was turning. Then I turned the passengers side and the drivers side did nothing. Went back to the drivers side and turned it and the passengers side did nothing. Each time the drive shaft was always turning.
I'll call the guy who sold me it and see what he says. Might be today, but most likely this evening.
thx, Dave J
Sounds like an open differential based on the description above. Given how it's working for you, meaning two equal patches of rubber, I'd be reluctant to swap it out
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OK, sorry it took me so long to get back to this, I was on a short vacation to Colorado with the wife.
I talked to the guy I bought it from. He said that he's seen this happen before on open differentials that have been run hard, or worn out from burnouts, miles, etc. I think he said if the shims (or the bearings) get too hot and wear out the diff can sometimes lay down two tracks on a straight line burnout, but can also act as an open around corners. Sounds like it would be a sweet deal if you want a posi, BUT, the trouble is that it won't do the same thing consistently.
So he has a 4.11 that he'll swap me for my 3.89 for $400. It needs bearings ($80) and a yoke ($50), labor ($175). So I can get a decent (but noisey) 4.11 trac-lok for $705. Does that sound reasonable?
Dave J
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Not if it is noisy. The Trac Lok should be as quite as church mouse.
Something is wrong with it if it is making noise.
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Sounds like your guy knows not of what he speaks. As noted, a Trac-Loc is quiet unless it's torn-up while a Locker will make noise, mainly clunking, on turns. Again, as to a open rear laying down twin tracks, hard to fathom, for sure. Mechanically, by what method can an open rear spin both tires? Does he need glasses when he does a rear end?
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So OK, it's time to take this thing apart :D. I'd like to see what's on the inside. Sorry Dave, know I'm talking about extra work but as someone somewhere once said, "a picture is worth a thousand words". Then again, you could just keep layin' down those double stripes until you convince yourself that you have a Trak Loc under there. Me, that's what I'd do 8). I sure wouldn't be eager to swap $700+ for something that needs work. No matter what you decide, once you get what you have now out into the light of day all questions will be answered (if it's working, quiet and consistent I'd leave it in and run the @^%& out of it). The guy you bought it from is suggesting that he sold you a shot rear end that doesn't make noise and acts like a Trac Loc. I do not know all the details or your supplier, but something just don't add up ???.
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My '66 Galaxie had a 4.57 open differential, and I always got an equal burn because I had Airlift air bags in the rear springs, with #5 in the left rear, and #10 in the right rear.
I would never install a Trac-Loc in a 9". They will burn up clutches and also the OEM cases tend to crack. They are not a good, or durable design, especially for 4x4's, or drag racing.
An Eaton Detroit Locker, or Detroit Truetrac are much better choices.
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So he has a 4.11 that he'll swap me for my 3.89 for $400. It needs bearings ($80) and a yoke ($50), labor ($175). So I can get a decent (but noisey) 4.11 trac-lok for $705. Does that sound reasonable?
Dave J
Doesn't seem like a good deal at all, I saw few rebuilt TrackLok rears, complete for $400 this weekend.
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Dang for $700+ you could do an ARB Airlocker and end up with an onboard air compressor to boot. Hell Dave it's a rat rod, just weld the spiders and be done with it. ;D
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Hm, I sure wish I knew something, (anything) about differentials. So just to refresh, the car is a Ratrod kind of look, but the engine, transmission, clutch pressure plate etc is completely and professionally rebuilt. Even though it's a 59 T-bird, it has power (front) disk brakes. It's mainly a street car, but I want to drag it maybe once a year. (I just have to be able to show a drag strip slip that proves a mid to low 14's time at a mile high) Yes, I have the fever. My name is David, and I'm a dragoholic. ;0)
Here's what little I know; please let me know what you think about each.
He said the ring and pinon gears were slightly pitted (due to rust) and that will make them noisy. But, he said they will still be plenty strong for a 400hp motor and it won't affect the strength or performance. (true or false?)
I think what he's saying is that the spider gears can get worn and burnt, and start to act like they are welded, thus it sometimes will lay down a two stripe burnout, but on a turn they break free and act as an open. Problem is, it's a crap shoot each time. (true or false or maybe?)
I said to him, well if that is true, then you sold me the 3.89 that was supposed to be noisy but solid, yet it didn't last. He said, that's because an open differential is not meant to be doing burnouts, and the burnouts are what most likely trashed it (true or false?)
He said the Ford diff clutches last pretty long. They have a larger diameter than a Chevy. Chevy's are no good. He said this 4.11 clutch still has plenty of the checkered pattern on it which means it will last quite a while. (true or false?)
Chilly, where did you see rebuilt Trac-loc's for $400? I found this on E-bay, http://www.ebay.com/itm/FORD-9-NINE-INCH-REAR-GEAR-TRAC-LOC-POSI-THIRD-MEMBER-28-SPLINE-OR-31-SPLINE/151323330908?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222008%26algo%3DSIC.MOTORS%26ao%3D1%26asc%3D23309%26meid%3D7503784206041329585%26pid%3D100005%26prg%3D9834%26rk%3D3%26rkt%3D6%26sd%3D161288632259&rt=nc
Seems like a better deal than mine as it's completely rebuilt, and I can sell my worn out 3.89 and get some money back.
Len, you are exactly correct. I can guess and guess forever, but I need to pull the pumpkin anyway if I'm going to be getting a posi (trac-lok). I can take pix, post them, and you great gentlemen will have a lot more than my lame explanations to go on. It's going to be a while though. Right now I'm in the middle of replacing the fuel lines with 3/8's inch. Bending this stuff is a lot tougher than bending conduit!
Regards and thanks to all, Dave J.
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Saw them at Carlisle. I actually picked up a complete Detroit Locker 3.70 third member for $525, that Ebay unit is out of line IMO.
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I would say his first statement about pitted gears may be true, although it is more likely that the gears are noisy because they are worn. His second statement about the spider gears being worn and acting like they are welded sounds like BS to me. However, he may be on the right track because if the shafts that the spider gears are riding on are worn, maybe they could jam and lock the wheels together in some situations. As far as burnouts trashing a one wheel wonder (open rear end), its always possible, but they should take some of that abuse anyway. My experience with Ford clutches is that they do last a long time, until you start doing burnouts; then you can burn them up in a hurry. If there is a checkered pattern on the clutches there is still clutch material present,so they have a while to go before they give up completely.
Two words: Detroit Locker 8)
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I was just going to reply when Jay popped in. I have to agree with every word he said. And I'll add that me and friends (when we were young) used to do "one wheel peels" in every conceivable way possible, on a regular basis, in all sorts of Ford cars and NEVER did we have any rear troubles except for the backlash that comes from a hundred thousand plus miles of use. He's also right on with Traction Loks, while they work, when you try to treat them like a posi the clutches have a very limited lifespan.
In my opinion, when you are purchasing a rear differential from somebody who rebuilds it with nearly all used parts, then you are going to get marginal performance and lifespan at best. Especially when those parts are robbed from many different used pieces that had already seated and worn into their original assemblies. And I get the feeling all those parts are robbed from junkyard rears that likely already had 100,000+ miles. It's like using used pistons and rings from a wore out engine in a fresh rebuild, it just don't work out well.
But mainly I agree with this statement 110%. This will end your problems forever :)
Two words: Detroit Locker 8)
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Thanks again gents.
What do you mean by "out of line" Chilly? Do you mean there's a possibility they are made with low quality parts and steel? I've heard that it takes someone with a lot of experience to be good at building rearends, and it concerns me too that these things might be mass produced.
Jay, the rearend is from an axle a guy traded him for some work. When he opened it up he found out it was in need of repair, thus the pitted gears etc. I don't convey what he has told me very well, but I'm guessing he was talking about the shafts for the spider gears is why it sometimes lays down two tracks.
So is a Detroit locker for strip only though? I want something that is street compatible. Do you guys know of a good source for a locker and how much that might cost me?
regards, Dave
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Detroit Lockers work great on the street, in my opinion anyway. You can buy them online at Summit for around $550; see the link below. These are the newer "soft lockers" that are quiet, yet positively lock the rear end.
http://www.summitracing.com/parts/dtl-187sl17b/overview/
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Check out quickperformance.com I have never used them but they list many choices. I may give them a try when I get my new center section this fall. Jim
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The Detroit locker looks great Jay, and they have a $50 rebate right now so my 28 spline would be $499.
But then I need the ring and pinon to make my 3.89 a 4.11, plus I'd have to pay someone to do the work.
The ones Jim pointed out from Quickperformance.com are $525 for any axle spline. A complete center section with 4.11 gears and the Detroit locker is $975. That one says it's good for up to 400 HP. I'm right around there, however if I ever want to move up to a 445 stroker etc I'll have to have a better case - nodular or aluminum takes it up another $700.
My head hurts.........I need to rethink this plan.
Hell, if I decide I'm going to do a 4.11 detroit locker, then I might as well take the one I have now (the 3.89) and weld it up as a drag setup, and run it ragged this summer.
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Thanks again gents.
What do you mean by "out of line" Chilly? Do you mean there's a possibility they are made with low quality parts and steel? I've heard that it takes someone with a lot of experience to be good at building rearends, and it concerns me too that these things might be mass produced.
I meant that $700 for a traction lock third member is out of line with what I saw for prices at Carlisle. I saw $375 on one, and $400 on several more, before haggling. Granted, I don't know particulars if they were used gears or what, but even with new gears it would seem they'd be considerably cheaper than $700. These are plain iron cases.
I've run Detroits on the street, granted in heavy trucks, but they weren't too bad IMO. They have a bit more lash so you have to be smooth on/off the throttle at low speed, but otherwise I found the driveability difference minimal. I like that fact that they're bulletproof and simple.
I picked up a complete 3.70 Detroit Locker rear at Carlisle for $525, used locker, plain case. Lots of guys run used NASCAR detroits without issue, they run $200-225 on Ebay so that's a consideration if you're trying to save some cash.
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Epay has a bunch of complete used 3rd members. Something else to make your head hurt. :) Your 28 spline axles seem to be an issue as most I looked at were 31 spline units. I'm always up for a used part if it saves me a buck.
http://www.ebay.com/itm/5-67-9-Inch-Ford-3rd-Member-31-Spline-Race-Car-Hot-Rod-/171355500574?pt=Motors_Car_Truck_Parts_Accessories&hash=item27e595701e&vxp=mtr
http://www.ebay.com/itm/5-29-Ford-9-Inch-3-Rd-Member-31spline-/171355494104?pt=Motors_Car_Truck_Parts_Accessories&hash=item27e59556d8&vxp=mtr
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I just picked up a Yukon aluminum thru bolt, Richmond gears, Daytona aluminum support, and bearing kit for under 600 at quickperformance. The prices are great shipping was a day early. I reused my spool. The guy that set up mine said the Yukon quality was as good as the high end mark Williams case.
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"Yukon aluminum thru bolt, Richmond gears, Daytona aluminum support"
You guys might as well be speaking German.
Quickperformances web site seemed very user friendly. Maybe I'll give them a call soon and see what they recommend. I'm sure they can explain things to me faster over the phone.
So is a "mini spool" the same as a Detroit locker?
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No. A spool keeps the axles turning the all the time. Lockers go in and out of "posi track". I run a a spool on the street with no problems but many don't like them on the street. What I was getting at with the Yukon case etc, was that its good for 1200 HP at a low cost. You can also get a nodular case from him around $240.
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I talked to Mike at "quickperformance". He said I should consider getting some 31 spline axles if I ever want to go up past the 400hp range. Better to do them when I do the third member as opposed to spending money twice. I have to agree, it'll be money saved in the long run. It's going to be a while before I get the bucks saved up though.
He also said that my scenario of an open acting like a posi is very possible, it's also telling me that something is really wrong in my differential.
After i get done with my fuel lines (hopefully this weekend) I'll pull that 3rd member and see what's going on inside. Any advise (or even instructions) on how to weld the thing as a complete locker? I'm sure there are some video's on youtube.
thx, Dave J
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Don't weld the spiders. There is a reason why NHRA and other drag racing associations forbid vehicles with welded spiders from competing on a real drag strip. If (more like when) the welds give up or the spiders shatter, the instantly driven side will easily put you into the guard rail. This is the same reason why spools require aftermarket axles; no longer are 31 splined OEM Ford axles still allowed with a spool.
2:11 REAR END
Welded spider gear rear ends prohibited in all classes. Four wheel
drive permitted per class requirements. Aftermarket axles
and axle-retention device mandatory on Top Fuel, Funny Car,
Pro Stock, Top Alcohol Dragster, Top Alcohol Funny Car, Comp,
Super Comp, Super Gas, Super Street, and 10.99 or quicker E.T.
cars; also mandatory on any car (regardless of class or E.T.) with
a spool.
2:12
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Thanks Bob, yeah, I don't plan on taking it to the track until I get a proper rear end in it. For that matter, I want to replace all the front end bushings and get a good alignment first too.
The weld up would be just to get by with a drivable car for now. If I open it up and the pins (or whatever they are called) for the spider gears are shot I thought maybe I can have it welded for now.
I'm not even sure how that works, but I found a local guy who teaches auto mechanics at the local northern NM college and he rebuilds trannys out of his home shop. I'll take to him or at least pick his brain.
thx, Dave
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The problem with open diffs and one Wheel burnouts
(low oil lewel ads to the problem)
Is the spidergears seizes to the pin that holds them (steel against steel)
Now it drives both wheels
And the pin starts to rotate and cut the pin that is there
to hold it in place. And the pin starts to destroy the hole
for it in the diff and you get a play thats gett bigger and bigger.
By now the diff is junk.
Finaly the pin for the spider gear breaks and the car wont move
Maby you still can save your diff with a new pin and two spidergears
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Thanks Heo, your explanation is actually one that I can understand, and makes sense. Like I said, I know next to nothing about diffs. Is it very difficult to remove the spider gears? And would I need any special tools to put new ones back in? (adjustments, shims, etc?)
If I take that route I can surely sell it and re-coupe some money for a detroit locker.
Dave
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I dont remember but i Think on the 9 inch you
have to open up the diff to change the spidergears
you have to remove the diff from the senter section
but no problem just ordinary hand Tools
Be careful to not change adjustment sidewise on the
diff and your fine
You understand when you see inside the centersection
two big..."nuts" to adjust the diff from side to side
Hard for me to explain in English but i Think you figure it out
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Thanks again Heo, when I eventually get it out I'll look at the gears and pin and see if they are in need of replacing. Hopefully it's not beyond repair. I'm quite good with mechanical stuff, but don't own any micrometer's and other tools, etc. that are needed to do a lot of car stuff. I'm OK up to a torque wrench and that's about it.
It's midnight where you are, have a good weekend!
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How about some good pics of this ill advised procedure. And a hint..... mig or rod (3/32 dia 7018 or 6010) works fine. Just make sure you preheat before you weld em. 200-250 deg will do. After welding let it cool slowly. Wrap the whole center section with a thick chunk of pink attic insulation to help slow the cooling process.
https://www.google.com/search?q=9+inch+welded+spider+gears&tbm=isch&tbo=u&source=univ&sa=X&ei=FHabU8-3K4mzyASftIFg&ved=0CC4QsAQ&biw=1600&bih=805
And don't weld the wrong gears. I noticed a pic of a ring and pinion welded together. Don't do that! ;D
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Or you can make a limited slip like in a Volvo 164
my son bought.
They had stuffed a pair of jeans in with the spidergears
;D ;D
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OEM 28 spline axle shafts are a very bad idea with an Eaton Detroit Locker. Any good traction, and they will break -- 31 splines are minimum, and aftermarket are much preferred.
You might prefer an Eaton Detroit Truetrac Differential ...
http://www.eaton.com/Eaton/ProductsServices/Automotive/AutomotiveAftermarket/Differentials/PCT_338418
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Thanks Doctor! Mike at QuickPerformance told me the same thing. He has the 31 axles, bearings, and seals for around $425. I'll do those when I buy the Detroit Locker. Do you guys think the standard center section case will be strong enough, or should i spend the extra $$$ and go with one of the others, ie, aluminum, or something else on this page?
https://www.quickperformance.com/Center-Sections_c_57.html
Dave
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Dave you are addicted lol , detroit lockers and 31 spline axles is the way to go , and honestly i would buck up for the better case imo see ng how you cheater slicks .. Bud
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Indeed I am Bud! So can anyone tell me if the first aluminum one is good enough, or perhaps the "S" (Strange) one?
I have NO idea what the differences are, and which one would be strong enough for 450hp.
The one for $399 is out, but that's not too bad because I want to use the detroit locker, and if I buy one of the $990 ones they give me a break on the cost of the Detroit Locker.
Dave J
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Aluminum is ok for weight savings on a strip car, but on yours I'd go with the iron "S" Strange unit. PLENTY strong. A Strange center section, Detroit Locker and 31 spline Strange axles is exactly the same set-up I have. Plenty good for 450-500hp.
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Excellent! Thx Doug.
Now if I can get the crow bar out and open my wallet.
;~)
Dave
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Oh, one more thing. Does anyone have advice on a gear ratio?
Here's what I have now; 4 sp toploader, wide ratio, 2.78 first gear with 28.5 inch tires.
I'm trying to decide if a 4.30 would be much faster than a 4.11 in the quarter. I'm worried I might have to shift to 2nd gear before I even get moving.
This is a street/strip car, but it won't really be highway driven. Maybe eventually in a few years I'll look at a 5 speed for the highway.
I was using this calculator http://www.csgnetwork.com/multirpmcalc.html
(the section at the bottom) and at 55mph with the 4.30 my rpm would be 2788. If I went with the 4.11 my rpm would be at 2665.
At say 96mph (roughly the end of a quarter mile) the 4.30 would be 4867. A 4.11 would be 4652.
I'm really lost on this stuff.
thx, Dave
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Go with the iron one , and you can get whole center section from roush - yates racing for $850.00 ish , iron case with detroit locker and gears set up with different ratios .. Bud
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430 s may be a bit much for your motor Dave , sense we are close we need to just set up 3.89 s , 400.s , 411 s and maybe even some 3.75 s and try them all .. lol Bud
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Give Dutchman Axles a call. I just had them do a set for my Galaxie, and they turned out great. They were only $380.00 plus shipping, with the bearings and retainers.
I think you are going down the right road. This stuff is expensive enought, but paying for it twice because you cut a corner the first time just makes it worse.
Perfect example, a friend of mine races off road trucks. When he was building the truck they used a complete rear end they got a good deal on. Full floater 35 spline axles, spool, nodular case, all really nice. Well it wasn't quite up to par with the build of his truck. Part way through the first season he broke both axles. Ok, now upgrade to custom 40 spline axles, drive plates, and spool for the old case. Next it was the ring gear because of the 5.46 ratio. Now fix that and go down a little to make it easier on it. Next it was the spool because it was a lightweight spool, the only one that would fit 40 spline axles in their existing case, and of course that ate some other parts up. Now he's working on replacing it all again, including the housing. He's spent twice what he would have originally, and its cost him several races as well.
The moral of the story is if you want to make 500-600 hp down the road, build the rest of the car for it now if you are changing parts out.
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Well said , you should always over build drive train imo Bud
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Perfect example, a friend of mine races off road trucks. When he was building the truck they used a complete rear end they got a good deal on. Full floater 35 spline axles, spool, nodular case, all really nice. Well it wasn't quite up to par with the build of his truck. Part way through the first season he broke both axles. Ok, now upgrade to custom 40 spline axles, drive plates, and spool for the old case. Next it was the ring gear because of the 5.46 ratio. Now fix that and go down a little to make it easier on it. Next it was the spool because it was a lightweight spool, the only one that would fit 40 spline axles in their existing case, and of course that ate some other parts up. Now he's working on replacing it all again, including the housing. He's spent twice what he would have originally, and its cost him several races as well.
The moral of the story is if you want to make 500-600 hp down the road, build the rest of the car for it now if you are changing parts out.
Off road trucks are BRUTAL on differentials and driveshafts!
Oh, one more thing. Does anyone have advice on a gear ratio?
Here's what I have now; 4 sp toploader, wide ratio, 2.78 first gear with 28.5 inch tires.
I'm trying to decide if a 4.30 would be much faster than a 4.11 in the quarter. I'm worried I might have to shift to 2nd gear before I even get moving.
This is a street/strip car, but it won't really be highway driven. Maybe eventually in a few years I'll look at a 5 speed for the highway.
I was using this calculator http://www.csgnetwork.com/multirpmcalc.html
(the section at the bottom) and at 55mph with the 4.30 my rpm would be 2788. If I went with the 4.11 my rpm would be at 2665.
At say 96mph (roughly the end of a quarter mile) the 4.30 would be 4867. A 4.11 would be 4652.
I'm really lost on this stuff.
thx, Dave
IF you are sure you won't be highway driving, the 4.30s would make the car feel really peppy and fun to drive.....in town and short distances. Yes, you will be shifting to second quickly, especially with the wide ratio tranny, but that is what will also get the car moving quickly. If you have plans for an overdrive in the future, they would work out pretty well. They also kill fuel mileage and wear motors out if you drive any longer distances without an overdrive. Thinking about hitting the interstate to hit the next town? Forget it. That RPM just shot up to 3550 for 70mph. That's an engine killer.
Realistically, if you want some decent street and road function, the 4.11s are about as deep as you want to go. 3.89s are a nice middle of the road gear for street and performance. Without an overdrive, none of them are 70mph friendly.
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Thx everyone!
Doug, I was leaning toward the 4.11's and I'm sure it will be plenty fun to drive around the local area. If I ever go all the way to Santa Fe for a cruise it's only 35 miles, and I can slow ride it 50-55 mph to keep the rpms down. This car won't see more than 1000 miles a year so the motor should be good for a long time.
BH107 and Bud, thanks for the reminder about spending the $ and getting what I'll eventually need up front. I've learned that the hard way a few times already. Example; my toploader for $900, then 2 years later I had a David Kee wide ratio large input output shaft kit installed. That makes for about a $1900 toploader that will one day be replaced with a 5 speed.
I'll check the sites you gents recommended today. I was going to go with "Quickperformance", but I'll see if rousch - yates and Dutchman axles come out to a better deal.
Thx again to all!
Dave J
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Roush Yates has a 4.00 nodular steel, detroit locker 31 spline for $850. Free shipping! Dutchman has the same thing but with 4.11's for $1330 and $50 shipping. Quickperformance has a 4.11 for $1319 plus shipping.
I'm thinking the Roush Yates at 4.00 is just fine for a 59 T-bird Rat project. That'll give me an SLR of 11.12. A 4.11 would give me and SLR of 11.43 Do you guys think it'll make that much difference? The car weighs 3680.
Dave
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Pull the trigger Dave get the 4.00 and locker from roush , I think they re a good deal .. Bud
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I think your SLR with the 4.00 will be fine Dave , it should make a big difference in leaving the line hard .. Bud
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Hey Bud, thx a ton. I ordered the 4.00, 31 spline, nodular case, detroit locker. $850 includes free shipping from the east coast - not bad. I'll have to change out the yoke to my yoke. Mines a 1330 and this one comes with a 1350. From what I'm reading online you have to use a crush washer and have a really stout work bench to rig it to. I read of one guy that rigged up his truck trail hitch to do it. I may just take it to my local mechanic.
Do you know if the crush washer is an item I can get from any auto store? And are they all the same size etc? I have no experience with diffs.
I'm also going to get the axles from Dutchmans per BH107 - they're $380.
Thx again gents, regards, Dave J
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Don't bother changing out the yoke, just get a 1330 to 1350 u-joint. It will save you the trouble of pulling the yoke and getting the crush set again.
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I had no idea I could do that, thanks a ton BH107!
Dave
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I haven't been able to find a 1330 - 1350 U-joint anywhere. Do any of you guys know where I can get them?
Dave J
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https://www.google.com/search?sourceid=navclient&aq=hts&oq=&ie=UTF-8&rlz=1T4GGHP_enUS533US533&q=1330+-+1350+U-joint
Try a NAPA store.
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google summit racing 1330 to 1350 ujoint. They show 3 joint part numbers. I went to clutch and ujoint service in the twin cities and they set me up with a HD version to this joint for my Comet.
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The Roush used 9" racing pig should come with a (shimmed) solid pinion bearing spacer. I can't imagine them using the standard crush spacer, but it would be best to call them and ask. A solid pinion spacer makes changing the yoke a simple R & R procedure.
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I went the other way for now, I got a 1350 forged Strange yoke for my 9". I am not ready for the shaft until I get my Tremec bought and installed so I got a Strange 1350/1310 universal, hopefully the shaft is not too far off and I can cheat till my engine and trans is done. It was cheap too, 25 bucks for the universal, not bad for the good part.
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Yeah, my local NAPA store has the 1330-1350 for $29.59. I won't be pulling the yoke. The pig arrived 2 days ago and looks awesome. Dutchman's will be starting on my axles today and should ship next week. It'll be fun to get that old T-bird a little sideways in the turns every once in a while.
sure appreciate all the input, especially Bud pointing me to Roush - Yates for the differential. $850 including shipping and tax for a complete pig, nodular housing, Daytona pinon support, billet yoke is way better than trading my open 3.89 and $705 for a standard case used Trac-loc.
Dave J
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Your welcome Dave , glad it worked out keep in touch .. Bud
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I had the Trac-loc in mine but went to the Detroit Locker. I have had a few and they always held up under the worst of torture. I cheaped out on the case and axles, I originally intended on a small block but with the 28 spline I can go to 600 ft pounds I am sure.
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You would push 28 spline axles that hard , i don t think i would i replaced my mine with moser 31 spline and they re 30% stronger than ford 31 spline . To me you can never have to strong a drive train .. Bud
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I had the Trac-loc in mine but went to the Detroit Locker. I have had a few and they always held up under the worst of torture. I cheaped out on the case and axles, I originally intended on a small block but with the 28 spline I can go to 600 ft pounds I am sure.
Are your 28 spline axles OEM? Either way I don't think I would push them that hard, I've heard of too many broken axles with much less HP than that.
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Yeah I got 28 but I do not think my 445 will ever reach anywhere near 600 and I will not run slicks ever. I may later on upgrade to Currie forged axles but I think I will be ok for now. I have seen 8.8 rears take serious abuse in my day . I guess it breaks down to vehicle weight, tires and how hard you hit it. My truck has no rear weight, four link, a short box and my rpm limit is 6500 which I will never drop the clutch above 3000 rpm. I can only put so much to the ground and everyone says I will never see over 600 hp so I'll just leave it alone.
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A lot of those 8.8 s have 31 spline axles in them though , and detriots all the way . Bud
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I finally got the old 3rd member pulled. Here are some pictures, they mean nothing to me, but maybe you guys can tell me if this looks like a normal "open" differential.
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Hm, it only added one of the pix. I think I should start shooting these photos in a lower resolution because after I make them small enough to post they look terrible.
Here's another picture.
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Looks like the trac- loc I have sitting in the barn. Limited slip standard ford.
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2X to that!
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How would I be able to tell if it's an open (as I was told by the seller) or a trac-Loc? Is there a tell tale sign some where that will let me know for sure?
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if you have a clutch inside the dif.(like a motorcycle clutch with multi discs).Its not an open one
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See Kevinstang's great write up; see Trac-Loc details near the end.
http://www.kevinstang.com/Ninecase.htm
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The simple way is an open differential has the pinion gears exposed so you can see them. A locker or limited slip has a closed case which contains clutch packs, springs or a ratcheting mechanism to apply power. There are exceptions like heavy truck and air locker rear ends.
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All my factory trac locs have recessed bolt area where they mount at the ring gear , kinda like a shoulder around the bolt where as the open one the bolt is level , that s how i searched for them in the junk yards anyway.. Bud
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Want another low milage one bud. It came out of my Comet with 40000 miles and 3:50 gear.n
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Yeah Jon you give me $ 50.00 and i ll take , will put it on my toro lawn mower ... lol Bud
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I thought of building a post hole digger out of it LOL
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Does anyone have a picture of how the strap style yoke and u-joints should look on a threaded yoke? My old one had the standard old u-bolts with nuts, but this yoke takes a strap and I've never seen one. Found one at a local parts store but the bolts are 1/4 too long, the yoke threads don't go quite all the way through.
thx, Dave
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Well, I found u-joint straps that fit across the 2 holes on the yoke, and also have the 1350 size caps. Problem is they don't reach the yoke when installed. (see the picture) Even though they aren't tightened down you can see the straps won't contact the yoke.
I'm guessing that I will have to call Roush Yates and ask them what straps to use, or where to get them as I can't find anything online about them.
I did find some articles about drilling out the threads on the yoke to be a 5/16" through hole, then use a u-bolt like the stock differential would have. Is that a bad idea??? I would think that the threaded ones are better just because that's what Roush Yates had on them.
I took it for a roll around the block and boy does that Detroit locker cla-clunk, cla-clunk, clu-clunk around corners! Are they really suppose to be that noisy? I don't mind cuz it's a Rat kind of car, but I just want to make sure it's normal.
thx for any input on these rookie questions.
Dave J
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They are a bit noisy , but worth it IMO .. Bud
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I took it for a roll around the block and boy does that Detroit locker cla-clunk, cla-clunk, clu-clunk around corners! Are they really suppose to be that noisy? I don't mind cuz it's a Rat kind of car, but I just want to make sure it's normal.
Dave J
Did you buy one of the NASCAR lockers? Those are pretty noisy, so what you are hearing would be normal. If you bought one of the "soft" lockers, they are much quieter. You can tell the difference by looking through the locker itself; the noisy ones are a straight bore through, while the soft lockers (at least the one that I have) has a hole straight through, but it is much smaller in diameter than the axles.
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Yes, I believe it is a NASCAR one. Here's the link, they still have another 4.00 just like it at the bottom of this page. http://www.roushyatesparts.com/Used-Ford-9-Inch-Rear-Gears-s/640.htm
Glad to hear that the noise is normal. It's not a problem at all for this car, it's kind of nice actually! I'm guessing it'll be pretty rough on the u-joints and tires if driven around the streets a lot???
Still like some opinions on the idea of drilling out the threaded yokes for u-bolts - anyone done this before?
thx, Dave
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I just called Roush Yates and they are shipping me the straps. Can't wait to get this on the road with and have some fun.
Dave
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I'm guessing it'll be pretty rough on the u-joints and tires if driven around the streets a lot???
thx, Dave
Well, I've run those lockers for years and haven't blown up any U-joints, but I always put 1350 series U-joints in my cars. Maybe smaller ones wouldn't do as well. In any case, I don't think you will affect the U-joint life too much.
As far as tires, well - you weren't expecting to keep those very long, were you?? ;D ;D
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Excellent point Jay!