Rear differential question
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Technically yes. But like many things you can probably get away with reusing the factory shims and just buttoning it up
It depends on what the manufacturer used to set the pinion preload, crush sleeve or shims, but if your plan is to visit the pinion bearings make sure to include a new crush sleeeve on your parts list, jic. Although compressed to provide the exact amount of preload that the pinion bearing needed when the rear end was first assembled, the old sleeve cannot be re-used. Thing here is that the new bearings are not totally clones of what the old ones were. They are also just as likely to have been manufactured and sourced "globally" instead of proudly wearing a made in USA or England or Germany or Japan source label. That "global" designation can mean that the tolerances they come with can fall within a fairly wide range of acceptability instead of consistently being just a few thou or less as used to be the case. All this means is that when you go to re-establish the pinion beaing preload, the amount of crush that the sleeve experiences may turn out to be more or less that what its predecessor did.
Maybe add some of that yellow dye/tooth marking paint to the list as well. Checking the pinion versus ring gear tooth contact pattern and depth is a monumental pain in the a** but also insurance that your new carrier bearings have not caused the carrier to move in or out, even with re-using the old shims.
Nick
Maybe add some of that yellow dye/tooth marking paint to the list as well. Checking the pinion versus ring gear tooth contact pattern and depth is a monumental pain in the a** but also insurance that your new carrier bearings have not caused the carrier to move in or out, even with re-using the old shims.
Nick
If there could be slight differences in bearing tolerances then the pinion and ring gear would never be aligned the same way again wether you readjust the shims or not. Does it not matter that a used set of gears align exactly the way they were? Just as long as it's within spec?
Why guess? Crossing fingers and hoping isn't the best approach to this, IMO. How would you know they're in spec unless you check them? And then if they're not in spec?...what would you be doing about that? Would you chance those gears singing to you at highway speeds, or clunking every time you put it in gear because of excessive backlash? I believe if you take a rear end apart for any reason, you should check the ring gear and spider gear backlashes at least when going back together. I'd personally do the pinion depth too if you pulled the pinion gear, because I'd use a new crush sleeve regardless. A few thousandths of an inch on backlash or pinion depth can make a world of difference on your pattern. And if you're going to reuse the gears, the wear pattern is already established and will be tougher to get the obvious pattern like it would be if you had new gears.
Gears and bearings will wear. And as they wear more, they adjust themselves more. And then you get more wear...bigger clearances, and so on and so forth when you check the bearings they're worn out and your backlash is probably bigger than it was when new. And that's why they usually put magnets on the rear cover. Even if it's within the spec on the loose end, how long until it wears to the point it's out of spec? It's not tough to tighten them up. It's just a PITA because it takes some time.
Obviously this happens over years, not weeks, but if you put new bearings in it without changing anything else, theoretically you should have things aligned just about where they were when new, taking into account any bearing manufacturing differences. But how will you know? And with the gear wear, the backlash will still likely be larger even if you put the gears in the exact same place.
All that to say this. While you can just re-bearing everything and likely get things to stay within specs with the same shims (and assuming you can do the right pre-load without crushing the sleeve more), you have to take it apart to do it anyway, so why not check it while you're in there to ensure you're within spec putting it back together so it'll last for 150K more miles? 1/2 the battle should likely be won with the pinion depth shim likely being the same one needed. But again, why guess?
Gears and bearings will wear. And as they wear more, they adjust themselves more. And then you get more wear...bigger clearances, and so on and so forth when you check the bearings they're worn out and your backlash is probably bigger than it was when new. And that's why they usually put magnets on the rear cover. Even if it's within the spec on the loose end, how long until it wears to the point it's out of spec? It's not tough to tighten them up. It's just a PITA because it takes some time.
Obviously this happens over years, not weeks, but if you put new bearings in it without changing anything else, theoretically you should have things aligned just about where they were when new, taking into account any bearing manufacturing differences. But how will you know? And with the gear wear, the backlash will still likely be larger even if you put the gears in the exact same place.
All that to say this. While you can just re-bearing everything and likely get things to stay within specs with the same shims (and assuming you can do the right pre-load without crushing the sleeve more), you have to take it apart to do it anyway, so why not check it while you're in there to ensure you're within spec putting it back together so it'll last for 150K more miles? 1/2 the battle should likely be won with the pinion depth shim likely being the same one needed. But again, why guess?
Good stuff so far. It is some basic tools needed to do this job correctly. Guessing, of course, has. 50/50 chance of it being ok.
You have to decide how you want it to work and how much you’re interested in it lasting for the life of the car. I’ve done plenty of rears that are popularly labeled as undesirable because they are weak. But they will live for a long, long time if setup correctly. At stock + 25-40% they should last forever. I have a 7.625 with a Torsen on that has lived through 450+whp for several years, and a factory 8.5 that lives at 750+ whp. Everyone would say I needed a Dana, 9”, etc.
You choose - I’d strongly urge you to head to Harbor Frieght and pickup a magnetic base dial indicator and digital caliper. Jegs and Summit sell budget oriented ones as well.
Or wing it :-/
You have to decide how you want it to work and how much you’re interested in it lasting for the life of the car. I’ve done plenty of rears that are popularly labeled as undesirable because they are weak. But they will live for a long, long time if setup correctly. At stock + 25-40% they should last forever. I have a 7.625 with a Torsen on that has lived through 450+whp for several years, and a factory 8.5 that lives at 750+ whp. Everyone would say I needed a Dana, 9”, etc.
You choose - I’d strongly urge you to head to Harbor Frieght and pickup a magnetic base dial indicator and digital caliper. Jegs and Summit sell budget oriented ones as well.
Or wing it :-/
All good advice here. Just buy the right tool for the job and verify the specs are correct.
You just have to line them up the way they were. . . which I've never done. I once paid to have used 3.73 gears installed by a guy who knew his 💩 and they worked great.
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