Crush sleeve/ diff setup??

[UTAHCRUISER]

I've got a question for those of you that have some experience with differential setups. I've got a '73 FJ40 with a sbc 350, 4.88 r&p's with ARB's, and 35's. The pinion uses a crush sleeve to set the preload on the bearings. Ever since I installed these gears, about 60K miles ago, I've had problems: about every 10-15,000 miles or so, the preload on the pinion decreases to the point that the flange starts to move around just a little bit, which in turn destroys the seal, causing leaks, and eventually gets loose enough that I have to tear it apart and replace the bearings and the crush sleeve.

I've gone through this process 2 times now on the rear diff and three times on the front diff- it seems like just about the first time I go and play hard in the rocks after rebuilding the front, it gets loose again. I've built a number of diffs without lockers in them, and have not had the same problems.

It seems that what is happening is that as the pinion rotates against the ring gear, in locked and maximum traction situations, the pinion is being pressed against the crush sleeve so hard that it is compressing and deforming the sleeve, thus loosening up the preload...

Has anybody else had this problem? Am I just messing up on the diff rebuild somehow? I have searched and found that you can buy solid machined sleeves for Toyota mini-trucks that allow you to eliminate the crush sleeve and use shims instead. I assume that the only reason for such a product would be to eliminate this problem. Does such an option exist for Cruisers?

I've tried using both the stock Toyota crush sleeves as well as the Chevy sleeves that are supplied with some of the diff rebuild kits.

Thanks in advance for any ideas/ solutions that you might have!

Chad

 

[I Lean]

The only way a crush sleeve can crush further after initial installation is for the bearings to wear enough to let them move closer together, or a bearing race not fully seated and moving.

It's possible your pinion nut is backing off, as well. That one's easier to tell, you can put a little tack-weld on the end of the pinion to keep the nut from rotating. (better than the staking, and easier to tell if it's moved later)

A solid spacer/shims is a better way to set preload, and that makes it so you can re-torque your pinion nut at will, too.

 

[UTAHCRUISER]

Hey Carl,
Thanks for the reply. I forgot to mention that I have staked the pinion nut, and every time when i look at it, there is no indication that it has loosened up at all. I suppose that I may not be fully seating the bearing races, but I use a press when installing them, and they don't seem to be able to move any more...

Do you know of any manufacturers out there that manufacture a steel sleeve for this particular application to replace the crush sleeve? Or, maybe any local machine shops that could machine one?

thanks again,
Chad

 

[waynehartwig]

The only way a crush sleeve can crush further after initial installation is for the bearings to wear enough to let them move closer together, or a bearing race not fully seated and moving.

It's possible your pinion nut is backing off, as well. That one's easier to tell, you can put a little tack-weld on the end of the pinion to keep the nut from rotating. (better than the staking, and easier to tell if it's moved later

This was my first thought, too... I always lock tite my nuts on... I also smack the pinion around with a hammer to make sure the bearings/races are seated. And use some diff oil on the bearings and surfaces during install...

 

[waynehartwig]

Hey Carl,
Thanks for the reply. I forgot to mention that I have staked the pinion nut, and every time when i look at it, there is no indication that it has loosened up at all. I suppose that I may not be fully seating the bearing races, but I use a press when installing them, and they don't seem to be able to move any more...

Do you know of any manufacturers out there that manufacture a steel sleeve for this particular application to replace the crush sleeve? Or, maybe any local machine shops that could machine one?

thanks again,
Chad

I think what you have to do is take one of your spent crush sleeves down and have a spacer machined the same size. I've never done it before, so I could be up in the night... I've always either used the crush sleeve or shims.

 

[I Lean]

Any machinist should be able to do it. Like Wayne said, take a used crush sleeve as an example, but keep in mind it'll "spring back" a little when you take it apart--so have the new spacer made a little bit shorter than the crushed sleeve, then take up the remainder with shims.

His point about lubing the bearings is good too--if you're putting them in dry, you could get a false preload reading and think you have everything snug when you really don't. I use a bit of grease, he uses a bit of gear oil--take your pick. (if you already do that, then disregard the last sentence )

 

[waynehartwig]

His point about lubing the bearings is good too--if you're putting them in dry, you could get a false preload reading and think you have everything snug when you really don't. I use a bit of grease, he uses a bit of gear oil--take your pick. (if you already do that, then disregard the last sentence )

Yeah, grease or oil, your choice..Just make sure you use SOMETHING. I only use gear oil because it's native to the differential and I don't have to keep assembly lube or something on hand. I always have lots of gear oil lying around...

Also make sure your knocking the pinion around to make sure the bearings/races are seated. That's really important. I typically put everything together without a crush sleeve and using the old pinion nut to set it all up, then put the crush sleeve and new nut with locktite on to finish.

 

[TimB]

Is there a chance a pinion bearing race is spinning in the case?

 

[UTAHCRUISER]

Is there a chance a pinion bearing race is spinning in the case?

There has been no signs of that happening- its always a press fit to get them in, and always hard to get them out again, and no signs of scoring or other damage to the race or the case.

Chad

 

[cruiseroutfit]

Chad, if you do get some solid spacers made, I would be interested as well... I have though about doing it a hundered times, but its far down the list. I could most likely get them machined in bulk at school too... I wonder if we could get a peice of DOM that is close enough?

 

[UTAHCRUISER]

Yeah, grease or oil, your choice..Just make sure you use SOMETHING. I only use gear oil because it's native to the differential and I don't have to keep assembly lube or something on hand. I always have lots of gear oil lying around...

Also make sure your knocking the pinion around to make sure the bearings/races are seated. That's really important. I typically put everything together without a crush sleeve and using the old pinion nut to set it all up, then put the crush sleeve and new nut with locktite on to finish.

I use gear oil too, for the same reasons. I also always smack the top of the pinion with a plastic mallet to try to ensure that everything is well seated.

Are you using the blue or the red locktite on the pinion nut? I have just been staking them, but I like the idea of tack welding the nut to the pinion, just in case that's my problem.

Its just confusing to me that this would happen so many different times. With each successive rebuild that I have to do, I am striving harder and harder to get things perfect, but the end result is always the same!

I've done some google searches for solid pinion spacers, and there are a number of companies that offer them, (although none for Cruisers) and they all cite the reason for using them as a cure for the crush sleeve loosening up due to shock loading of the pinion, so i figured that must be my problem.

But, it doesn't sound like any of you folks are having this problem, so I guess that points to faulty assembly on my part... I guess I'll try again!

Thanks for the replies, btw!
Chad

 

[UTAHCRUISER]

Chad, if you do get some solid spacers made, I would be interested as well... I have though about doing it a hundered times, but its far down the list. I could most likely get them machined in bulk at school too... I wonder if we could get a peice of DOM that is close enough?

Hey Kurt, so does this mean that you have had this issue as well, or do you want them for the simplicity of replacing the pinion seals? I though about using some DOM, but I wonder about the strength of that material. Also, you would have to machine the ends on a lathe to ensure that they are perfectly flat and parallel to each other, which wouldn't be a big deal if you have access to a lathe!

Chad

 

[cruiseroutfit]

Hey Kurt, so does this mean that you have had this issue as well, or do you want them for the simplicity of replacing the pinion seals? I though about using some DOM, but I wonder about the strength of that material. Also, you would have to machine the ends on a lathe to ensure that they are perfectly flat and parallel to each other, which wouldn't be a big deal if you have access to a lathe!

Chad

I have never really run into it... I was just on the phone with Darrell (PO of Cr.Out., he has literally set up hundereds of Cruiser diffs). Said it was never a major issue. I have had Carl setup quite a few LC 3rds, too my knowledge none have been an issue...

4130 tube would be fine I think...

 

[waynehartwig]

I use gear oil too, for the same reasons. I also always smack the top of the pinion with a plastic mallet to try to ensure that everything is well seated.

Are you using the blue or the red locktite on the pinion nut? I have just been staking them, but I like the idea of tack welding the nut to the pinion, just in case that's my problem.

I use red.... I smack both ends of the pinion. I also hit the sides of the yoke as I turn it.

 

[sbr]

you can also put a little locktite on the ouside of your races before you press them to make sure that they do not spin