My 427 SOHC Build..... Finally the time has come!

[cobracammer]

Hey Jared,

Wiggle- No.  I can turn the pinion back and forth a good 1/2 to 3/4 " in either direction.  When I do this, I can hear the gear teeth touch at the end of the movement in each direction.  In my mind this would  translate to the backlash of the ring gear.  I think (from reading online) that the acceptable backlash on a ford 9" is .006" to .010"....... If I can turn the pinion clock wise and counter clockwise about 1/2 to 3/4 of an inch...... that seems like it would translate to a HUGE backlash  LOL

Interested to get it out and take a look.

[cobracammer]

Parts and tools should be coming today, but in reading through an old "SA" manual I have on building Ford 9" rear ends, I saw a little statement about "Crush sleeves".  It states that they are not recommended for high horsepower or racing applications.  Instead, they suggest the solid pinion spacer with shims to dial in the proper pre-load.

99% sure the rear differential I have is using a crush sleeve, so I also have a solid pinion spacer and shims on their way.   Want to use the solid one for the rebuild in case it was a "too high horsepower" issue that caused this 

[cobracammer]

OK everything arrived (parts and tools) and yesterday I got started on the removal.  I did not want to pull the whole rear end, so I got to work pulling the 3rd member while still under the car.  As you could imagine, in a modern car, there is not much wasted space like in the older cars.  It took a good 3 to 4 hours, and took loosening quite a bit of "bits" in order to rotate the housing down enough for the "pumpkin" to clear and come out.

Just this morning, I got it mounted up on the engine stand in a 3rd member mounting fixture and took my first measurement.  The original ring gear has a backlash of 0.009"

Reading online, it appear that proper ring gear backlash for a for 9" is between 0.006" to 0.010".  So it appears this is ok?

With the 3rd member mounted in the stand, when I turn the pinion yolk back and forth, there is play and I get a metal on metal "clink" in both directions.  Its not smooth.  What else should I measure (and in what order) before I start pulling the thing apart or as I pull it apart?

Thanks all

Edit:  Wanted to make sure the gear set in the original 3rd member was ACTUALLY a 3.89:1, and it is confirmed.  Didn't think to count the teeth when I first started this project.

This 3rd member is still so new, that the original white gear pattern paint is still highly visible.  What I did notice is that the gear paint is pretty thick at the bottom of each gear (valley), but there is no paint at all at the top of each gear tooth (almost like the pinion needs to be moved closer to the ring gear).  I havent wrapped my mind around how the pinion could be too far away, but the ring backlash is perfectly within spec?

[cobracammer]

OK, this morning I tried something out of curiousity.  I took a bit of the marking compound and put it on 3 of the teeth.  I put my hand on the ring gear at the top (simulating a little bit of resistence) and turned the pinion back and forth on the painted section.  When I rolled the ring gear back around to inspect..... Ah Haaa!  Both the drive side and the coast side are centered, but all the way at the bottom of the ring gear (Toe?).  They need to come up quite a bit to be centered on the ring gear teeth!  The charts on line say to increase backlash to make this happen.  Any suggestions where I should go from my current 0.009" backlash?

[BattlestarGalactic]

A typical "new" set up should have just a slight click and very slight rotation of pinion.  If you have 1/2 or more turn then something is wrong.




Moving the pattern Toe and Heel takes changing the shims under the pinion support(sounds like you need MORE shim).  Then adjust backlash.

You initially set up the pinion depth, which should center your pattern on the ring gear.  If you don't have the tools or measurement, then you just have to watch the pattern with paint until it is where you want it.




I just replaced the gears in my '69 F100.  With minimal tools, I reused my solid sleeve then checked rotation torque with inch/pound dial wrench I purchased some time back for working on my Harley.  It was within spec.  I reused my shim pack under pinion support and things lined up well.  I set backlash and applied marking paint.  I then used my drill with large socket to spin the pinion.  It had a nice pattern and very noticable smooth operation.  If something is wrong, you will see/feel the problem when using a drill to spin it.  It will buzz/vibrate if set up incorrectly.  That buzz will turn into a loud RING when driven on the road.

[cobracammer]

I just waned to see what would happen if I adjusted the backlast (gave it a bit more backlash) as it states that it should move the pattern away from the bottom toward the top of the gear tooth.  Like I stated before, I was at 0.009" backlash from base.  I turned the adjusters on each side  loosening one, and then tightening the other.  Both were moved 1 hole on the adjuster.  Retorqued the caps, and set up the dial indicator.  I was at about 0.012" to 0.013" of backlash and yes, the pattern moved up a little toward the top of the ring gear tooth, but not enough.  I tried again with moving the adjusters a bit to give a little more backlash, this time around 0.015" and tried the pattern again.  Not really any change from the first move.

I am guessing that you can only adjust backlash out so much before it starts having a negative effect. 

What I also noticed is that although the pattern was moving in the correct direction (toward the top/ outside of the ring gear, it was still favoring the top side of each tooth (needs to move more toward the bottom of the V in the gear.

I am guessing that by lessening the shims on the pinion, it would move the pinion deeper into the housing and thus the pattern would be deeper into each tooth (toward the bottom V of the gear tooth.

What I cant check is what the pinion depth for the original/ Current ring and pinion setup should be (and thus make sure its not out of spec).  Is this just where you sort of try different things until you get the correct pattern?

Main questions:

1. From reading online and the books I have, it seems like the ring backlash should be between .006" all the way to .015" (these are the min and max from different sources).  I also read that for a used gear set, you should shoot for around .010" of backlash.  Are these correct?  What am I aiming for a used gear and likewise for a new gear?

2.  If both the backlash and the pinion depth can be adjusted, which is better to adjust?  Is it better to aim for a specific backlash and then adjust the pinion depth as needed (always going back to get the target backlash).  Or is the pinion depth "non negotiable" and the backlash needs to always be adjusted? (in this case since I do not know what the spec pinion depth should be as I purchased this as a complete 3rd member)

Thanks guys.  Its sucks bad having the whole rear of the car/ axles/ suspension/ sway bar/ end links just exploded all over the garage.  Really want to get this car back together as efficiently as possible  :0)

[cobracammer]

Thanks battlestar.  I was posting as you posted, so it seems from what you say, if you don't have the specs, then play with the shims until you get the correct pattern.

May I ask what are your thoughts on backlash?  What did you aim for/ end up with?

[BattlestarGalactic]

I'm a rookie at this actually.  I've done a few, but no means an expert.   This was last summer, so don't recall specifics, but I know .007-.012 range is good.

As for backlash, tight is fine, but if you are fighting it, shoot for the middle and call it good.  Working those side rings can be challenging to get super accurate.  A little nudge goes a long way.  You are trying to set the side bearing preload while this is going on also.  I recall a buddy many years ago, setting the rings so that the ring gear had NO lash.  Then using one side, crank on the ring to increase backlash.  When you get your .010, the side bearing preload would be in range.  I've never checked, but never had bearing problems either.

Roll the ring gear against the pinion(put drag on the pinion) and feel the sensation.  Like I mention, any "buzz" to it will indicate something is not right and will cause a noise when driving.  If it rolls smooth, then it is good and will be quiet.  Running it with a drill worked really well for me.  Get an socket adapter for your drill, that is what I have.

[C8OZ]

If I've read this correctly, you're getting backlash measurements from .009-.015", but that doesn't fit at all with the issue of 1/2 to 3/4 turn of free travel originally checked at the yoke.

A couple of things come to mind. Is it possible the "slack" you were feeling wasn't gear backlash at all, but movement of whatever locker unit you're using while one wheel/brake was dragging a bit? Hope that makes sense. Otherwise, if a pinion bearing has gone south or your crush sleeve is "overcrushed" it may be that the pinion has somewhat "fallen in" at the moment, and your backlash checks are giving a deceptive reading at one end of the pinion's new "range."

You're getting great advice. I just don't see where the big slack was coming from.

I think I'd make absolutely sure the pinion preload is real. Even a couple of taps with a brass hammer in each direction front to rear to confirm it hasn't migrated.

[cobracammer]

I am not sure if I wrote it wrong, but the back and forth slack I get turning the pinion yolk is not 1/2 to 3/4 of a turn.  It was 1/2 to 3/4 of an inch  LOL  it makes a metal on metal "clink" when i turn it either way.  Sorry for any confusion.

[C8OZ]

No, that was ME writing it wrong, sorry. 
I meant inch, but the .009" you found just isn't enough for that range and a sound, especially before removing the oil.

[cobracammer]

Here are pictures of the gear pattern right now.  Cant remember if I said it, but in 4th gear and above, holding speed, the thing Whistles/ howls so bad, you can not even hear the engine.  Let off the gas and it goes away completely.  So coast seems ok, but drive is wayyy off I am guessing

First photo is coast side

Second photo is drive side

[BattlestarGalactic]

Way too deep.  Need some shim under the pinion.

As you manually turn the pinion you will feel a vibration/buzz as the tooth walks off the ring gear.  Once you shim it out, you will notice that buzz not be there.

[cobracammer]

Ok.  Took it all apart to start fresh.  This is what I found:

First of all, there was no "preload" on the carrier bearings!  I spun the ring gear with one hand and it kept on spinning for about 30 to 40 seconds before it stopped.  LOL. Strike 1.

I tightened up the carrier bearings to get a preload to where when I spin the ring gear with one hand, it keeps spinning freely for a second or 2 before the drag stops it.

Second, as "battle" said, I needed to add some shim(s) to get my pattern to move higher on the ring.  When I remove the daytona pinion housing, there was already 2 shims on it.  They were both 0.020" each for a total of 0.040" total.  This amount of shim was getting me the pattern I posted above with a ring gear backlash of 0.009".  I must have tried 5 or 6 combinations of additional shims ( some I even tried twice.  Where I ended up is an additional 0.017" shim for a total of 0.057" ( still able to maintain 0.009" backlash wiyh a bit of adjusting.  I would say that the pattern is directly in the center of the tooth possibly favoring a little high, but I can still see a little yellow paint line at the very top.  Tried 0.060 and 0.065", but did not move it any deeper that I could tell.  Coast side is still pretty low on the ring gear and favors the root/ root, but thats kind of where it was at ( maybe a little better) from the start and I had no howl when coasting.

Will try putting it back together tomorrow and maybe I can get away with returning my new ring and pinion set?  Wish me luch and thats for the input!

[cobracammer]

Sadly it seems its not fixed (noise starts at a slower speed now).  I am going to take a few weeks break, and then pull the whole thing again and install my brand new ring and pinion by US Gear (Strange).  :0/