8000 miles and out of warranty... Found the rear axle noise....sucks Off to find proper shims and bearings and seals and ... I thought the shim pack on driver's side was supposed to be cupped for retention, and I've never seen one done with 15 shims..........
That is definitely a pile of shims. Makes you wonder if the rebuilder was too lazy to get the right shim / thickness, or didn't want to properly repair a more severely damaged housing?
GM made them with one cast shim, and the replacement shims are packs like that. If you don't get enough preload, they'll fall out, eh? or even if you do, eventually the bearing race will spin some, and wear them down, or let them move out of place. The best solution is to machine a solid shim once you figure out how thick it needs to be. I don't know of any shops that do this?
I'd have liked to see it done with a spacer and a couple shims like the passenger side or a set of the locking sammich style. That's a mess.
In production GM tended to use a single thick shim on each side of the diff case to properly position the case and set pre-load. These cast shims were machined on both surfaces and were approx. 1/4" thick. The actual thickness was varied in .001" increments. The GM axle techs must have had a rack of 20-30 various shims of differing thickness to choose from. Once the correct dimension were determined a single shim was installed on each side of the case. Less fumbling and measuring involved for an easier, quicker job on the production line GM did not offer these thick shims as a service replacement part, though many techs in the field saved the ones they removed when rebuilding an axle assembly. For service, GM offered a thinner, narrower spacer (roughly .170" thick) to take up most of the side bearing clearance. For the rest of the clearance a thinner shim of varying thickness was added to the spacer to make the final setting. These shim were sold in packs of 5 in .001" increments. Ideally, the finished job required only a single spacer and a single shim on each side. As I recall there may have been five different shim packages available ranging from something like .065" to .095". I suspect that most GM dealers don't bother to stock all these items but they are probably still available on special order.
The .170 spacer was 9780883, the shims came in packs of 3 sizes, as follows happy shopping! NOS stuff is fun to buy, sell, and use
I ordered up a set of the sammich shims. I'm guessing the set up was a bit loose too, allowing the thin shims to walk out
The aftermarket is where those thin shims come from. I've set up ring and pinions in dozens of 12 bolts, "back in the day." In the late 70s through the 80s when I was actively doing this, shim packs were not available, except for pinion depth. Even so, it would be near impossible to get a pack of shims that thin in there with enough bearing preload, at least without a case spreader. I'd just make 'em from scrap hydraulic cylinder tube. Eventually, I had a pretty good stock of carrier bearing shims
I guess machine shop time is pretty expensive, but most any shop could rough part off pieces of material on the lathe as Mike suggests, then surface grind to finished thickness.
This style aftermarket shim pack might help. Thick base shim with a raised lip to center the thin adjusting shims and the thick cover.
Those are what you need and buy or build yourself a case spreader. Another lost art ! I have seen more hacks working on rear ends than shops that know what they are doing.
I had a coworker help me do all new bearings, seals, etc in my daily (254k Suburban). It was really interesting to watch him set them all up. I had never done one and was amazed at his ability to do it so efficiently. I really appreciate the process...but the end result speaks for itself.
I feel ya. I set up a few, but kills so much time for me referring to my Motors manual, etc. I burn a couple of weekends doing it. Only “easy” one was a Ford 9inch. That only took me maybe 10 hours… Next one I’m paying a shop and picking it up when it’s done. Like Clint said “A man has got to know his limitations”
Yep, that's a great Clint (Dirty Harry) quote. But I truly think Harry was referring to OTHER guy's limitations!
Got it all back together including replacing the leaking pinion seal. A new ratech 12 bolt car seal to replace the truck seal. Pinion torque was 15 in lbs on the old seat and reset to the mark plus a touch yields 18 in lb on the new seal. The Yukon sammich shims were stacked .228" on the driver side and I reused the spacer on the passenger side. Backlash came in at .007, middle of spec. Carrier can't be removed without a pry bar. 18 shims reduced to 5. Just gotta fill it and go for a drive.
15 mile ride today and much better. Quiet acceleration and I took it up to 60. Mostly quiet on deceleration with a light whine on deceleration from 45 to 40 ant then quiet again. Much better than it was.
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