Pinion Gear Moved?

just had my axles regeared to 4.56's 8.25 rear with an auburn ls. Have been driving the setup for about a month now, two trail runs on it. Sunday was out wheeling and all the sudden back in started grinding-thought the limited slip wasnt disengaging and got it home. Finally opened up the rear end today to find the pattern on my gears was set so the pinion was really deep but also looked like there was a better pattern when it was set (like there were two wear patterns almost). Most shocking was the carrier for the limited slip had a gear pattern in it. Yes the carrier has a pattern where the pinion gear has taken chunks out of it and worn it down im guessing causing the grinding. Pulled the driveshaft off and used a pry bar to see if the pinion was loose and i couldnt pry it any direction seemed tight as an arrow, pinion nut seemed tight too although i dont have a socket large enough to check the torque on it. Any ideas on what might have caused this, and what to do to fix it. I didnt install my gears and the mechanic that did is 8 hours away from me.

woah... sounds like a pretty serious problem... i would be making a call to that guy and having some serious words...

Last time I saw a dif that looked like that, the housing looked like this:

But of course the damage to the carrier was MUCH worse. X2 on the serious problem.

Better pics would help!

It does look like the pinion was way too deep but I would expect the grinding should have been there from the start. There's just about no way for the pinion to move if it was installed correctly. Please post up some clear pics showing all parts of the diff and carrier and we can give you a better idea of what's wrong.

ok it will be a bit before i can do that but i will for sure. It was driving perfectly fine up until this so i was thinking that the pinion would have had to moved. After doing some more research the backlash can change pinion depth as well, so is there a chance something has changed the backlash on the axle throwing the pattern off and moving it enough. Other things ive read are that the crush sleeve? or the pinion bearing itself has gone bad and under stress allowing the pinion to move.

The crush sleeves included in most aftermarket gear kits are too soft for the 8.25. After a little use, and getting warm, they will soften and let the pinion move further into the gear set. I blew my 8.25 up twice before discovering that hear on naxja, and confirming it with a cat from Randy's Ring and Pinion.

Have your gear guy fix the rear end, but get a crush sleeve from a Jeep dealership. In this case, OEM parts really are better.

If the pinion nut is still tight than the front pinion race likely was not seated at install, and after subjected to some load, seated itself. Ive seen this happen several times. On the 8.25, the front race needs to be countersunk below the step in the housing. This is often overlooked

StylerG said:

just had my axles regeared to 4.56's 8.25 rear with an auburn ls. Have been driving the setup for about a month now, two trail runs on it. Sunday was out wheeling and all the sudden back in started grinding-thought the limited slip wasnt disengaging and got it home. Finally opened up the rear end today to find the pattern on my gears was set so the pinion was really deep but also looked like there was a better pattern when it was set (like there were two wear patterns almost). Most shocking was the carrier for the limited slip had a gear pattern in it. Yes the carrier has a pattern where the pinion gear has taken chunks out of it and worn it down im guessing causing the grinding. Pulled the driveshaft off and used a pry bar to see if the pinion was loose and i couldnt pry it any direction seemed tight as an arrow, pinion nut seemed tight too although i dont have a socket large enough to check the torque on it. Any ideas on what might have caused this, and what to do to fix it. I didnt install my gears and the mechanic that did is 8 hours away from me.

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wow talk about some fantastic answers

is the crush sleeve and race something i can change on my own with the proper tools. Im thinking the backlash and shims are already set so could i pull the carrier out and change those things easily? Like not having to completely reset the gears????

As far as I know (I'm a knucklehead when it comes to gears, only know what I've read) the crush sleeve is part of what sets the pinion bearing preload, so you probably want to at least have a torque wrench for that. If you're replacing a bearing race, I believe (?) it'll also throw your backlash out of whack since the new bearing race may be machined slightly different.

Again, this information is worth about as much as the paper it isn't printed on...

StylerG said:

wow talk about some fantastic answers

is the crush sleeve and race something i can change on my own with the proper tools. Im thinking the backlash and shims are already set so could i pull the carrier out and change those things easily? Like not having to completely reset the gears????

Click to expand...

Unfortunately, when you replace the crush sleve, you have to pull the carrier to re-set the pinion pre-load. It has to come apart. The back lash is set with adjusters on the side bearings after the carrier is re-installed. Pretty much needs re-done.
Also, the odds of the gear set NOT making noise are pretty slim. If you had a pro shop do the gears, I'd ask them to re-do with a new gear set and bearings - on their dime.

You can also replace the crushsleeve with a spacer/shim set-up to fix that type of problem forever(makes changing pinion seals a snap too).

RCP Phx said:

You can also replace the crushsleeve with a spacer/shim set-up to fix that type of problem forever(makes changing pinion seals a snap too).

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Thats what I am running

http://ratech.stores.yahoo.net/ch8axpa.html

so if im hearing this right i cant just pull the carrier and remove the pinion, replace crush sleeve with factory part and same shims and put carrier back in?

am i also right in understanding i will need new bearings for the rear end upon reassembly?

If this happened than the pinion nut would be loose too.

cal said:

The crush sleeves included in most aftermarket gear kits are too soft for the 8.25. After a little use, and getting warm, they will soften and let the pinion move further into the gear set. I blew my 8.25 up twice before discovering that hear on naxja, and confirming it with a cat from Randy's Ring and Pinion.

Have your gear guy fix the rear end, but get a crush sleeve from a Jeep dealership. In this case, OEM parts really are better.

Click to expand...

Not exactly. You need to pull the carrier and see what is up with the pinion. If the pinion is loose but the pinion nut is tight, then It is certain that the pinion race was not seated in the housing at the original install. If the pinion nut is loose, than the nut backed off for one of these reasons:
-no loctite
-overcrushed crush sleeve and then re-tightened nut
As for a crush sleeve failure, this is very unlikely.

StylerG said:

so if im hearing this right i cant just pull the carrier and remove the pinion, replace crush sleeve with factory part and same shims and put carrier back in?

am i also right in understanding i will need new bearings for the rear end upon reassembly?

Click to expand...

thanks for the clarification! Now when i pull the carrier im definately looking at resetting my gears? Im asking because i have no clue how to do that meaning i wouldnt even be able to drive my jeep somewhere to get it fixed. Like i said the shop that did it was 8 hours away so ill have to take it to someone local this time and am figuring that if i am able to hand them the parts and exactly describe the problem then i can keep my cost down. On the other side, if i can get away with learning how to throw some gears in and keep the learning curve down because most things will remain set then i wouldnt mind buying the tools to try it out.

About ordering a new ring and pinion because of whine-any other thoughts on this?

Just Differentials said:

Not exactly. You need to pull the carrier and see what is up with the pinion. If the pinion is loose but the pinion nut is tight, then It is certain that the pinion race was not seated in the housing at the original install. If the pinion nut is loose, than the nut backed off for one of these reasons:
-no loctite
-overcrushed crush sleeve and then re-tightened nut
As for a crush sleeve failure, this is very unlikely.

Click to expand...

If the pinion race was not seated then the pinion would have moved away from the ring gear when it did seat. It's possible the backlash might have changed due to some error with the adjusters but it would have to change an awful lot to put the pinion into the ring gear that far. I believe the gears were set up way too deep and when the pinion wore into the ring gear far anough it made contact with the carrier. In any case it looks like the shop that did the gears should not be doing gears. It totally looks like installer error. You need at least a new ring and pinion and maybe all new bearings as well.

StylerG said:

thanks for the clarification! Now when i pull the carrier im definately looking at resetting my gears? Im asking because i have no clue how to do that meaning i wouldnt even be able to drive my jeep somewhere to get it fixed. Like i said the shop that did it was 8 hours away so ill have to take it to someone local this time and am figuring that if i am able to hand them the parts and exactly describe the problem then i can keep my cost down. On the other side, if i can get away with learning how to throw some gears in and keep the learning curve down because most things will remain set then i wouldnt mind buying the tools to try it out.

About ordering a new ring and pinion because of whine-any other thoughts on this?

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I don't recommend trying to set up gears without training. You might be better off getting another shop to fix your diff and demand a refund from the previous shop. I would not let them touch it again. Also carefully inspect the housing for any cracks or defects. This kind of failure looks like the result of a badly too deep pinion setup.

StylerG said:

thanks for the clarification! Now when i pull the carrier im definately looking at resetting my gears?

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On the C-8.25, you need to reset the backlash when you R+R the carrier. Again, it's set by adjusters, not shims. The pinion doesn't need reset.(except that in this case, the pinion is the problem)

StylerG said:

Im asking because i have no clue how to do that meaning i wouldnt even be able to drive my jeep somewhere to get it fixed.

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You don't know what you're doing, and you don't have the tools, don't take it apart. 'Not trying to be an a**, just stating the facts. There are some very fine threads machined into the side bearing caps for the adjusters to run on. If you remove the caps without backing the adjusters off, you can damage the housing and make it impossible to reinstall. Once it's apart, the adjusters themselves are a royal PITA to get back in, and it's easy to cross thread one or both while doing it. Screwing around with this setup could leave you looking for a new axle.

StylerG said:

Like i said the shop that did it was 8 hours away so ill have to take it to someone local this time and am figuring that if i am able to hand them the parts and exactly describe the problem then i can keep my cost down. On the other side, if i can get away with learning how to throw some gears in and keep the learning curve down because most things will remain set then i wouldnt mind buying the tools to try it out.

Click to expand...

If you know somebody that's familiar with the 8.25, and has the tools, it's not hard. It's not really worth buying all the tools you need just to do it once.
Have you tried to contact the shop about the problem yet? 'Lot of expensive parts may be screwed up. Any kind of warranty?

StylerG said:

About ordering a new ring and pinion because of whine-any other thoughts on this?

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:dunno: Gonna be a toss-up. chances are, with the end of the pinion rubbing on the side of the dif. case, there are going to be chips and ridges worn into the ends of the pinion teeth, as well as a severely irregular wear pattern on the gear face itself, it's going to make noise. How much is anybody's guess. If the shop will stand by their work, I'd have them spring for a new set. If I had to do it myself, I'd try it and see how bad it was, as long as the gears aren't too visibly damaged.(I can get away with that, because I have setup bearings, shims etc, and a friend of mine has access to all the specialty tools)