FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: Clark Coe on September 13, 2019, 03:22:30 PM
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I need help with the input shaft fitment of a new TKO600 five-speed installation in my 1968 Mustang equipped with a stock 390 with a stock Ford crankshaft. The TKO input shaft is too long and splines hit the bronze input bushing. When bolting the new transmission to the stock Ford GT/CJ bell housing (C6OA-6394D), the input shaft interferes with the input bushing with about .060” before the trans and bellhousing meet.
(https://i.postimg.cc/SKLqBQ79/Robeson-toploader-TKO600-input-length-compare.jpg) (https://postimg.cc/kV5k8mHM)
I ordered the TKO600 with the short input shaft option for Ford FE engine. The TKO600 as delivered, has the distance from the transmission mounting surface to the tip of the input shaft at 6.672”. The 428CJ big in-big out (RUG-AE2) close ratio top loader I am replacing measures 6.03”. That is a .642” difference. I was expecting new transmission to be a complete bolt-in and not to be this far off.
(https://i.postimg.cc/1t9PsxJj/Robeson-toploader-TKO600-input-length-compare-2.jpg) (https://postimg.cc/WDfxwyRG)
The stock Ford bronze bushing is fully seated into the crank flange. The bushing has always sat approximately .100” proud of the flywheel flange, is this normal? This old configuration has functioned perfectly in this car with this top loader for the last 39 years.
For a solution, it may be possible to remove the bushing and machine a step relief in the backside, outside diameter and move the bushing deeper into the crank flange. The pocket depth of the hole in the crank flange in deep enough to accept the current (short) input shaft. There must be a two diameter step in the crank flange hole.
I do not want to disassemble the transmission and have the input shaft shortened at the splines. Is there a better way?
Is the 6.03” input measurement from my Big In/Big Out correct? I have searched for this measurement and have not been able to confirm the 6.03”.
Did I really receive the short FE input option? My vendor said that I did and that I have an unusual transmission and bell housing. :-\
(https://i.postimg.cc/Px2Hq67r/CJ-Bellhousing-C6-OA-6394-D-in-my-68-FB.jpg) (https://postimg.cc/jwwmghKG)
Do 390 top loaders have different input lengths than big in/big out 428CJ close ratio top loaders?
I need some expert input please, summer is almost over and I have not driven my Mustang this year.
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Modern Driveline. 208-453-9800
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From the photos and your measurements it looks like you didn't get the short input option. When I did my first conversion the BBF option was not available so I had to get a spacer made by McLeod and it was nearly the same thickness as the difference you are showing.
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Alan is correct. You'll need the spacer. Modern sets them up so other than the disc/spline pattern it fits in all the factory locations, including the shifter.
They also give those of us who are veterans a 10% discount. Great service as well.
-Keith
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Use the short input shaft kit, not the spacer. The spacer compounds concentricity tolerances which you don't need. Dialing a bell in by itself can be challenging, I wouldn't add to it.
The short input shaft kit is about $300 and it takes about 15 minutes to swap it. It's not like working on a Toploader, the input shaft is keyed and it slides right out after you take the bearing retainer off. The kit comes with a bearing retainer and an input shaft.
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This was Modern Driveline in Caldwell, Idaho. The best numbers I can find is that a small block toploader should have a input shaft length of 6.49" and a big block toploader will be .38" less than that at 6.11"....this was from a Richmond Super Street 5-speed resource chart. 6.11" is sort of close to my field measurement of my BI/BO toploader of 6.03"
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Brent, Thanks for your reply. I would have purchased this from your business, but I really wanted the lowered cut down case to clear the brace in the tunnel.
I DID order and pay for a short shaft option. I am guessing that maybe I received a GM input shaft.
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Clark, I apologize for not doing a good enough job of reading your post. I see what you're talking about now.
A short input TKO should bolt up to any FE bell, with the exception of a truck bell.
A typical TKO input shaft is about 7.2" long. A standard TKO depth bellhousing is 7.050" from the block flange to the trans flange, so if you were to sit it on the floor block-side down, and measure from the floor to the trans face, it would be 7.050".
A Toploader bell should be about 6.400" deep if measured the same way that I just described.
So, if you compare a standard length TKO input shaft and a short input shaft, there's gonna be about 3/4" difference.
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Brent, Thanks for your reply. I would have purchased this from your business, but I really wanted the lowered cut down case to clear the brace in the tunnel.
I DID order and pay for a short shaft option. I am guessing that maybe I received a GM input shaft.
My short input was the same length as my RUG-AE2, I think you may have the wrong one
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Your toploader is a big block version. The TKO looks like the wrong one.
Can you line them up side/side and compare the spline and snout lengths? Is it just the snout or are the splines too long also(likely)?.
If it's the splines, then it needs a different shaft. If just the snout, then a cut off wheel will fix it easily.
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Battle star may have hit the nail on the head. Way back in the 90’s I had the input shorted by .600 to fit my top loader bell. The look after the spline cut was like yours,it looks like they didn’t trim the pilot shaft back . See that groove? That is the old end of the splines.
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Looks like a snout cut will bring it all back inline.
Separate issue but the diameter of that TKO input shaft looks a lot smaller than the old T-loader shaft. Can't therefore believe that at least the shaft is as strong as the old Ford piece.
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Can't therefore believe that at least the shaft is as strong as the old Ford piece.
You'd be surprised......
I've got TKO 600's, unmodified, behind 740 hp BBF's. They're very stout and their torque rating is rated "continuously".
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Interesting. Must be tougher steel than Ford used.
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More splines help as well.
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Brent is correct about the stock Ford FE bell housing I am using. Checked it last night and it is approximately 6 7/16" (6.43") deep. Most all of the components in this installation are proven stock Ford parts. I did upgrade to a new steel 30 pound McLeod flywheel.
(https://i.postimg.cc/x89LJcJn/6-seven-sixteenth-bell-depth.jpg) (https://postimg.cc/8Jn7xkm0)
Here is the interference with the TKO splines with the pilot bushing. The transmission was not tight to the bell housing, there was a .100 gap between the two.
(https://i.postimg.cc/XJkCb42h/Pilot-Engagement.jpg) (https://postimg.cc/ftkL7nQj)
How much distance does a clutch disc require to float on the spline to relax and disengage?
(https://i.postimg.cc/yxncFsc9/Clutch-Splines.jpg) (https://postimg.cc/fStVs4HT)
The short (6.03") top loader input shaft was tight enough to leave a slight witness mark on the bronze pilot bushing. The pilot bushing is not proud as I first reported.
(https://i.postimg.cc/c4TsWV1j/20190913-203250-1.jpg) (https://postimg.cc/MvMkb3Qb)
(https://i.postimg.cc/jjNfMzyR/Input-Compare.jpg) (https://postimg.cc/nsFMz9dW)
It appears that this input shaft is not the required short FE shaft that this installation requires. But I am not sure what Modern Driveline provided with my order. Do vendors re-manufacture shortened inputs by machining lengthened splines? Notice the two colors of splines in the above picture. Also, what is the purpose of the groove in the middle of pilot diameter?
Not sure what my approach will be with Modern Driveline. In a phone conversation, they seemed convinced that they had supplied the correct input shaft, but no way will this work without machine work, and that is not what I paid for.
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Tremec typically supplies short input shaft kits. There's a part number for it that includes the input shaft and the bearing retainer.
Once upon a time, they were backordered indefinitely, so guys were making their own out of standard length inputs or GM inputs. It's possible that this one was a custom and something was amiss on it.
I gave dimensions up above for the input shaft lengths. Maybe you could compare.
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TCKT5729 is the short input kit for a tko600 and TCKT5727 for the tko500. He mentioned the splines hitting the pilot so shortening the end isn't going to help. With the pictures you have taken I would send to them and be asking them to send me the kit at a minimum. If not, I would be asking to return the whole thing for a refund and buy elsewhere.
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I would be wondering about my crankshaft thrust bearing on this one...
(https://i.postimg.cc/W3vkCh7g/Pilot-Bushing.jpg)
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I would be wondering about my crankshaft thrust bearing on this one...
All is good with the thrust bearing. That groove is not as deep as it looks in the photo, barely can catch your fingernail on it. I had the oil pan off during this transmission deal to freshen up the pan gasket that was seeping. Thrust bearing clearance was within specification.
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So the splines are too long, not the pilot. That will require either a new input or removal of input and cut the splines back. I guess that is why they offer that spacer, but that is not what I call "the right" fix. The splines need shortened.
You have plenty of spline for the disc to float. It only moves 1/16" or so when the PP is pushed and the disc is allowed to spin.
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I would ask them to give you what you payed for or send it back and buy from some one who stands behind what they sell.Would this input work with a truck bell?
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If it was me I would just have a new pilot bushing machined down, doesn't look like it needs much since you say you can just catch you nail on it and it isn't deep.
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Well I'll throw my 2 cents worth in and hopefully not muddy the water too much. I had a very similar situation on a 63 Galaxie while installing a TKO 600. One key difference was that I was using a truck bellhousing which is slightly deeper than the original 63 FE bellhousing. I had a kit for a Galaxie that was supplied by American Powertrain which included a pilot bearing, not a pilot bushing. This pilot bearing was a much smaller OD (outside diameter) than the pilot bushing in my crankshaft, obviously this smaller OD pilot bearing was not going to fit in the large hole my original pilot bushing was in. The picture of your pilot bushing would appear to be the same OD as what was in my crankshaft. When the TKO 600 was mounted onto the truck bellhousing it looked very similar to what your pictures show that the splines bottomed on the bushing with a substantial gap remaining between the bellhousing and transmission case. What I did find after I removed the pilot bushing was that there was another hole in the crankshaft that I was not aware of due to the pilot bushing covering it up. This additional hole, deeper in the crankshaft, was the correct diameter for the pilot bearing that was supplied with the transmission kit. So, installing the pilot bearing into the smaller and deeper hole in the crankshaft resolved that problem for me. I should also mention that while I was struggling with this issue I had an old 352 core that I was making comparisons to with an original FoMoCo crankshaft and it only had the larger diameter hold for the pilot bushing. My crankshaft was a Scat 428 stroker crank, which had the large hole (fit the bushing) and the small hole (fit the bearing). I do have a more extensive write up about this and some other issues on the TKO installation, I didn't want to dump the whole thing in the middle of this post. If you are interested in reading the entire write up, PM me with an email address and I will send it to you.
I would agree with some of the other responses that it really looks like you didn't get the short shaft.
I would be especially aware of the crankshaft end play at every step of the way as the potential for disaster is present if end play is not present.
My kit come from American Powertrain and I had some real issues working with them and the issues I had. Interestingly Modern Drive Line actually helped me out in resolving my problems even though my kit come from a different vendor. I think all these vendors do their best to resolve the issues but sometimes you just have to work a little harder to make it clear to them what the issue is or find the right person in the organization that can fully grasp what your up against. I'd be hounding Modern Driveline on this as I think they are little more knowledgeable on Ford applications then some of the others plus it's their kit and they want you to be happy with it..
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Talk to them, I don’t think you got what you paid for. I will post what a good one looks like later.
FYI I ran into this with an old small block TKO non 500/600 with a modified chevy input. Even with a truck bell it hit. That one I even had to cut the bearing retainer because the throwout collar was too long
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I have the short shaft on my TKO600 as well and the splines were hitting the pilot bearing before the trans was all the way mated to the bell. My 428 crank seemed like it had a shallower pilot hole than my old 390. I machined a step in the pilot and it works great.
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Here is mine, hopefully you can zoom in and get some use. These are old pics, no ability to measure for you, but Clark you know it works from the ride down Maple Street!
(http://i.postimg.cc/Fsw-5LGvn/Inputs-zpsdcb196b2.jpg)
(http://i.postimg.cc/SN5rMBp0/Oldandnew2-zps499c5fdd.jpg)
(http://i.postimg.cc/bNW1V1J4/Oldandnew-1-zpsb160a875.jpg)
and no, I don't curl that anymore, that was 14 years ago :)
Since then, torn bicep, 2 bulging disks in neck, spinal stenosis, you name it, the mighty fall fast....but as the song says, "Not as good as I once was, but I am as good once as I ever was" LOL
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I too run a SCAT crank and use the “inner” pilot bore with a 5.0 Mustang roller pilot bearing.
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Here is mine, hopefully you can zoom in and get some use. These are old pics, no ability to measure for you, but Clark you know it works from the ride down Maple Street!
Ross, thanks for the comparison pictures, those will help with when I contact the transmission vendor.
Yes, you are correct about that memorable Saturday morning ride at Cars and Coffee, your Mustang hooks up and gets with the program. The story of my ride in you Mustang has been shared with many.
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I have the short shaft on my TKO600 as well and the splines were hitting the pilot bearing before the trans was all the way mated to the bell. My 428 crank seemed like it had a shallower pilot hole than my old 390. I machined a step in the pilot and it works great.
That looks like a fairly simple solution and may be in my future. My installation requires approximately another .200" of clearance to bolt everything together. I plan to hydraulically jack the pilot bushing out of the crank and find out how deep the first step is and why the pilot bushing will not drive deeper into the crank flange. Trying to make up my mind whither to use bread or grease as the hydraulic medium.
Thanks for the picture, drdano.
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Cant you just chuck a countersunk in a cordless
drill and countersunk the pilot bushing where it is?
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Cant you just chuck a countersunk in a cordless
drill and countersunk the pilot bushing where it is?
Ha!….that would be too easy, Heo! However, that is a really good idea. I am considering making a back cut on the bushing to at least make it sit flush with the crank flange. Your countersink relief will be an easy way to gain more clearance if required. There is contact at the splines to over come and also .100" (2.5mm) gap to close the gap between the bell housing and transmission mounting surface.
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I have the short shaft on my TKO600 as well and the splines were hitting the pilot bearing before the trans was all the way mated to the bell. My 428 crank seemed like it had a shallower pilot hole than my old 390. I machined a step in the pilot and it works great.
That looks like a fairly simple solution and may be in my future. My installation requires approximately another .200" of clearance to bolt everything together. I plan to hydraulically jack the pilot bushing out of the crank and find out how deep the first step is and why the pilot bushing will not drive deeper into the crank flange. Trying to make up my mind whither to use bread or grease as the hydraulic medium.
Thanks for the picture, drdano.
I bought a pilot bearing puller from HarborCrap. Ground the hooks slightly to fit the I.D. of the pilot. Works like a champ and no grease explosion when the bearing pops out.
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Okay drdano, you have given me another excuse to purchase more new tools....thanks. The HF pilot bearing puller has favorable reviews. I forgot about the grease explosion mess. Also do not want to waste bread and not have any for my morning peanut butter toast and coffee breakfast.
One tool from HF that has been very handy for this project, is this Pittsburgh scissor transmission jack. $100 minus 20 percent coupon = $80. Simple to use. I am too old to lift transmissions into position by hand, or maybe I never was that strong, but I forget. Balancing a manual transmission on the floor jack has never been very successful for me, either.
(https://i.postimg.cc/PqQbZrVf/Transmission-Jack-Small.jpg) (https://postimages.org/)
I do not have a lift in my garage, so this little transmission jack works great for folks that have to work on cars sitting on jack stands. I have been laying on my back on the concrete quite a bit for this TKO 600 project.
(https://i.postimg.cc/pTVfBb3f/Installation-Progress-Aug11-2019-Small.jpg) (https://postimages.org/)