Never messed with any of this diff stuff, still learning. A solid pinion spacer really sounds like the way to go. yeah, maybe a little tedious, but sounds like a crush sleeve has to be manhandled and is easy to screw up.

Any thoughts on this?

https://www.quickperformance.com/GM-...s_p_21511.html

This guy covers why crush sleeves are difficult, although he never gets to actually putting on the spacer.....

 

If you're the kind of person that can screw up a crush sleeve, you shouldn't be farting around in a differential anyway.

Get a GREAT BIG LONG breaker bar, and an equally GREAT BIG LONG lever on your pinion flange tool, and slowly sneak up on the spec. Now having said that, you see PLENTY of people who work in shops, and make Youtube videos, explain and show that they take the handy impact gun and zip them down that way. I myself had the housing supported on jack stands, with one 3ft bar on the flange holder braced against the concrete, and my full body weight on another 3ft bar on the pinion nut, and I had the crush sleeve set in a couple minutes.

Ratech? I think? sells an alternative crush washer that requires less effort. When I bought my parts, I bought kits for the bearings and gears, both came with stock style crush sleeves, and I ordered the fancy high tech crush washer too. I managed to screw up one stock style crush sleeve, because I had to take the pinion gear apart after it was assembled, but the second one worked out fine. Murphy's Law of Wrenching - They're cheap, get an extra or two if you're worried about it, if you have a back-up, you certainly won't need it. If you don't have it, you'll have to order one, and wait for it.

 

lol - I'm the kind of person that can screw up an elbow joint. that is my real concern.

 

I will not use a crush sleeve if I can help it. Always a solid spacer with selectable shims if one is available.

I have a 4' piece of bar stock with 2 holes (well, more than 2; maybe I should say, 2 for each of several yoke bolt patterns) along the edge at the end(s). With that, and a long breaker bar with a 2' piece of pipe slipped over the handle, I'd estimate that I can put 400 ft-lbs of torque on a pinion nut without breaking a sweat. Enough that I split a 1¼" socket once... now that I know how tight that is, I stop before reaching full gorilla. Usually at chimpanzee, or maybe even only orangutan sometimes. I have NEVER had one back off of its own accord after tightening. With a crush sleeve on the other hand, you have to quit tightening when the proper bearing preload is reached; and my kind of luck is, it takes about 300 ft-lbs to get the sleeve to start crushing, and then as the sleeve collapses as it reaches the correct degree of crush, the torque falls off DRAMATICALLY. Like, to not much more than 100 ft-lbs. Not enough to guarantee holding the nut still. THOSE, I have had back off on me. That's why I won't use them unless I have no other choice.

I make a pair of pinion bearings to use for setup if I don't already have a set for what I'm working on, by honing out the bore with a brake cyl hone so they slip on and off the pinion easily. Then I put on nice new ones after getting the setup (pinion shims) where I want them. Although to tell the truth, shims go with the HOUSING, not the gears (the housing is the inaccurate and inconsistent part but gears are very consistent with certain exceptions), so virtually always, if I have the original shim for a housing, I just put back in a new one of the same thickness and don't bother with "setup" at all. Which seems to be a benefit... that gives me one less opportunity to screw something up. Which is generally a good idea where I'm concerned.

I also heartily recommend replacing the yoke. One look at a stock one compared to a replacement, and you'll never bother with the crappy stock crap again. Even a non-performance replacement, just a stock grade like Omix-Ada or something, makes a stock one look like a Neanderthal chiseled it out of a soft rock with a piece of a harder rock. And of course, the seal seals to the YOKE, and almost always, the place that the seal runs on it, is wore out and likely to leak. No sense taking that risk as well as all the others.

 

I was wondering about this. The Chevy 10 bolt rebuild book says you can re-use your factory shims if all you are doing is replacing bearings. But the service manual says don't even try re-using them. Is that what you are suggesting? Also, how do you get them in? Do you use a special tool? I see guys in videos tapping them in with chisels, but that seems like a lot of force in one small area.

Oh yeah, I'd be that guy that snapped the tool, then my elbow would be next. nobody got time for that.

oh, and also thanks for the yoke suggestion, I think, now I gotta go learn about yokes......

 

I would not "re-use a factory shim" on a pinion installation.

I DO however, use a NEW, better quality made of harder metal, replacement pinion shim, of the same thickness.

Not sure what you're asking about "tapping them in", but that sounds like carrier shims, not pinion shims. Those, I would NEVER re-use factory ones, not least because they are almost always entirely unusable to begin with due to wear, but also because, they aren't even steel. They're cast iron.

Most R&P shim kits have 4 thick steel washer type shims (usually .100" or so each) for the carrier, and a wad of much thinner ones. Carrier shims need to be somewhere in the .250" ballpark but vary considerably over a wide range. Anything from .225" to .275" is common. Correct way to handle those is, stack up thinner ones in between 2 of the .100" ones, to make packs of whatever size you need.

The carrier bearings need preload, same as any other tapered rollers. Problem there is, you have to drop the carrier into the bearing saddles somehow, with "too much" shim in there to allow it to just drop in. The carrier plus bearings has to be MUCH larger than the housing minus shims. Best way to select those is, stack them up to achieve the desired "backlash", which for a 7½" 10-bolt wants to be maybe .007" - .012" (play between the ring and the pinion) while still allowing the carrier to "drop" in; then, after setting the shim packs correctly this way, add as much as .010" to BOTH sides, which ends up locating the carrier in the same spot between them (more or less centered) but with the bearings already partly compressed. The "book" way of getting thicker shim packs in there than will "fit", is with a tool called a case spreader, which bolts onto the housing and bends it out open as you tighten it. I don't have one, and IMO using one distorts the center casting of the rear in a way that makes it more likely that hard use will distort it again in the future, PERMANENTLY. Instead I use 2 YUUUUUUUUUJJJJJJE C-clamps on the bearings, and compress them that way so that the carrier can drop in between the shim packs. I tend to set backlash toward the upper end of the spec because gears GROW as they get hot (see your thread about using heat to shrink bearings on) and therefore the backlash GOES AWAY over time when gears are loaded heavily. Again, not necessarily "more than" the spec, but, toward the top end. I tend to aim for .010" - .012" of backlash in a 7½" 10-bolt.

I like to set bearing preload in general, toward the HIGH side of its spec. Not "too" high, just, toward the high side. So, in a 7½" 10-bolt, I tend to shoot for 22 - 25 in-lbs of torque on the pinion bearings, and just absolutely as much as I possibly can attain on the carrier bearings, which in reality, is never really all that much to begin with. Given how it has to be assembled, there's really NO WAY to get "too much" preload on the carrier bearings.

I'm not a big fan of trying to set up gears with a "pattern". Not to say that it "doesn't work", or "is wrong", or "don't do it", or any such; only, that it's too hard for most people to reliably interpret, too nebulous, too prone to change as the gears wear in, and overall not a clear-cut go/no-go indicator of much of anything. If the pinion shim matches what the housing needs, and the backlash is "OK", then the pattern will be "OK", no matter what it "looks" like with gear marking compound. I guess a good way to put it is, if you set it up correctly in the first place, then if the pattern isn't GROSSLY fornicated, you're golden. It doesn't make sense to try to "fine tune" the pattern beyond that.

 

I'm with Drew on this.
I recently set up the 8.8 that is now under my car. Same method. I went to the recycling yard and paid a dollar or two for an aluminum bar that was 1/2" thick, 2" wide and a little over three feet long. I made a relief cut and drilled it to fit two of the pinion flange bolts. It worked perfect and allowed me to sneak up on the preload I wanted with relative ease. I put a 3' pipe over a breaker bar for the 1 1/16" pinion nut. I ended up at 19 inch/pounds which is on the lower side of the preload recommendation (16-29) so right where I wanted to be.



It does take some strength (it is a lot of force required to tighten it to preload) and time (you only want to apply 15° of sweep at a time) but it is pretty easy to do. I got crush sleeves from O'Rielly auto parts for $1.69 each. Use red Loctite on the the nut and you're done.
Skip spacers and their whole trial and error of measure preload, disassemble, reassemble, check preload. Rinse and repeat 1-20 times until you reach the correct preload.

 

Tibo's aluminum piece is pretty similar to mine, except mine is steel and a bit longer. Same idea though. Looks a whole lot like mine. Look at the principle, find a material piece that's readily available to you, and go from there.

Only thing to me is, a crush sleeve is prone to not provide as much "holding" power on the nut over the long term, as being able to tighten the nut until you can hear it screaming for mercy, the way you can with a solid spacer. The crush sleeve MIGHT (not saying it "will") leave the nut too easy to back off because it's simply not tightened enough up against something. But it CAN work; I just don't feel confident that EVERY time, it WILL work. I HATE IT when something I do FAILS to work. Which can always happen with a crush sleeve, no matter how perfectly you get it set up initially. I want the 100% certainty if I can get it. The small amount of extra initial effort is worth the long-term confidence that it won't come back all loose and fornicated.

 

Hey Sofa, since you mentioned the new yoke I did some internet searching, but only finding 1350 series for over $100. Omix-ada comes up with nothing. Got any good links?

 

Sure, got me there. Solid spacer wins in that regard. However, how many millions of rear axles have GM, Chrysler and Ford built over the years that use a crush sleeve, that see hundreds of thousands of miles over decades with power levels all over the place? I've never read accounts or articles speaking of the dangers of a nut backing off a crush sleeve. It probably has happened out of the millions of rear ends that have seen service but I think that if assembled correctly with an anaerobic adhesive its about as common as a crankshaft pulley backing out.

 

https://www.drivetrainspecialists.co...3r-series.html
https://www.summitracing.com/parts/yga-41090/overview/
https://www.summitracing.com/parts/yga-41088/overview/

Not sure the difference between the 2 Yukon ones... haven't ever used either of those

I mentioned Omix-Ada because I got one made by them for a Cheep (Bland Cherokee) not too long ago; just as an example of a stock-ish-replacement kind of a product, as opposed to some hard-core racing thing like you might get from Currie or Moser or the like.

Tibo, you're right, GM and others have made MILLIONS of rears that successfully get through their warranty period. But the most frequent total failure method I've seen in high-mileage rears, after the bearings wearing out of course, is the nut backing off. I had a 78 El Camino once that did that and wiped out the gears, so I went to the buzzard nest and got another rear, and that one did it too. (early 7.5" with the small tail bearing)

 

It sounds like the bearings were worn which would remove the preload on them and allow for slop. If that is correct do you think a solid pinion spacer would suffer the same fate?

 

No, I wouldn't think so...

Consider how a pinion goes together. You have the 2 bearings, a nut that tightens down on them, and you tighten it until it reaches the correct preload on the bearings. The thing in the middle (pinion) spins while the thing around the outside (housing) sits still. It's exactly the same as front wheel bearings, except that on the front wheels, the part on the inside (spindle) sits still while the part around the outside (hub) spins. And of course, on front wheels, the nut is a free-turning type, and is retained by a cotter pin. Well, in fact, back in the day, the same method was used on rear ends; classic (50s) trucks still used a cotter pin, for example. Problem is, with the higher revs and power levels that came about with the introduction of V8s in the late 50s, it became too easy, and commonplace, to shear the cotter pin. That's when the crush sleeve idea was introduced.

If you look at a crush sleeve, the inner edge of the sleeve sits against a "step" on the shaft of the pinion, and the outer edge is pressed in by the inner race of the tail bearing. The nut presses in on the race, which tries to crush the sleeve, and as the sleeve crushes, the play in the bearings decreases, until finally, the play is all taken up and further tightening begins adding preload. At some point, adequate preload on the bearings is reached, and you quit tightening; at that point, the nut is retained by the force against the crush sleeve. The roller/race contact is not involved in that part of it. That's why when you start tightening against a crush sleeve, you have to put some hundreds of ft-lbs on the nut to begin crushing the sleeve, even though there's an eighth-inch of play in the bearings still.

However, the fit of the yoke splines to the pinon splines, isn't "perfect"; couldn't be, or it would be impossible to assemble. Or, to make splines that precise, would be so expensive to make that it would be impractical. There's always a tiny bit of slop that allows the yoke to spin just slightly - maybe only a fraction of a degree - on the pinion. But the fit isn't quite "perfect". THAT'S what backs the nut off.

Furthermore, the force that the R&P puts on the bearings, tends to PUSH the pinion out of the housing (eject it toward the drive shaft) when accelerating, which is of course resisted by the pinion's head bearing. The big one; think of the pinion as being shaped like a tadpole swimming into the housing, and the names make instant sense. BUTT: when DECELERATING, or in reverse, the gear tooth force tends to PULL the pinion into the housing; and the thing that resists that is the tail bearing. But the part holding the pinion securely in the tail bearing, is the crush sleeve; meaning, sudden deceleration, or for that matter accelerating in reverse, both tend to crush the crush sleeve FURTHER. When that happens, the nut loses its tightness, and becomes very easy to back off by way of the yoke's tiny rotation on its splines.

The problem to be solved then is, that the sleeve in its act of crushing, doesn't necessarily provide enough solid strength to tighten the nut to a sufficient torque to guarantee that it will stay put, and even more important, that the torque on the nut will remain at its initial level forever. That's what the solid spacer allows... (a) you don't have to stop tightening the nut when the correct preload is reached, and (b) nothing about it can deform further under the stress of operation. Instead, you tighten the nut against a stack of solid metal that doesn't ever "give"; and even better, doesn't EVER just go away due to usage of the rear.

IMO Loctite or the like is totally inadequate to prevent this. The force available to try to turn the yoke on the pinion is MUCH greater than any organic material like that would be capable of resisting. Even staking the nut like is sometimes done is not necessarily enough to positively retain it.

 

The pinion nut shouldn't come off on it's own, and the crush sleeve really doesn't retain the nut. The nut should be a locking nut with thread locker. At least on brand F stuff, you use a new locknut and it comes with the thread locker already applied.

The reason shims are popular (beyond not needing super-human-retard strength) is for durability in racing applications. A 10 bolt is going to shat upon the mattress long before the crush sleeve stops applying preload to the bearings.

 

great conversation guys. (for a gear head anyway, my wife would be asleep by now) so far, the only argument I'm hearing for using a crush sleeve is because you can and because its 15 bucks cheaper......... well, actualy 13 because you will likely screw one up before you get it right.

 

The only question is - How many times do you want to take it apart? Every time you want to try a different pinion or carrier shim, you're going to be tearing the differential apart. When you think the pattern is pretty good, you can either do one more tear down and reassembly with the final shim set and new bearings/seals, etc and torque the crush sleeve, or you can start trying different spacer shims, tearing it down every time to try a different one, until that's worked out.

Really it's just more labor, to solve a problem that's not likely to be an issue. If you plan on running slicks, and shocking the drivetrain on launch, and figure the shock might collapse the sleeve, sure go for the solid spacer. But I would contend that the 10-bolt will be a liability long before the sleeve gives out.

 

i’m thinking in my situation where i’m changing bearings only that i measure old crush sleeve, install solid spacer same size and done. in theory anyway.......

 

Not quite that easy. There are normally two sets of torque preload values you can use, one set for if you have new bearings and another set if you are reusing the existing bearings. Existing bearings need less preload, new bearings need more preload because they will open up. If you measured a crush sleeve on a set of worn in bearings and put in new bearings you'd be too loose. You really can't get away from the trial and error of a solid pinion spacer.

 

Damn, quickly learning that chevy 10 bolt diffs are so simple, yet so easy to screw up.

 

Setting up the solid pinion spacer on my 9 bolt was one of the easiest parts of the whole process. I measured the crush sleeve, added some thousands to the spacer stack, torque the down and measure the preload. I think I was done at the 3rd try. And like sofa said, I just cranked the nut down to spec when I was done, I didn't have to mess with trying to make sure I didn't over torque/crush the sleeve

 

Looks like Denny's Drive Shaft has some good prices. https://www.dennysdriveshaft.com/c39...h_10_bolt.html

 

Would you mind giving a little clarification on what you are doing with the C-Clamps? Where are you mounting them?

 

I put them on opposite edges of the outer races of the carrier bearings to press them together GENTLY somewhat, so they'll fit down in between the shim packs, which at that point are already laying in the saddles in the pumpkin. Kinda like putting a bit too much preload on them for that period during installation - just enough to allow the carrier assy to drop into a space that's otherwise too small for it to fit into - then letting the extra preload off after it's all together as far as it can go that way, so that there's still a reasonable amount of preload on them after installation.

The "classic" method of accomplishing this is with a "case spreader"; a frame sort of object that bolts across the whole thing and uses acoupla big screws to press the housing apart by bending it open. The purpose is the same... to allow an assembly that's too big to fit into the housing, to be installed anyway; and then the bearings to remain under preload when all the tools are removed.