Thunderracing.com sells a solid pinion spacer for the GM 10-bolt rear end to replace the OE crush sleeve. They note that it should be installed by a professional who knows how to install this particular component? I have done all my rear ends in the past, and the only thing I could guess them referring to is the spacer doesn't have to be "crushed" like a typical pinion crush sleeve. Am I right? Or completely clueless???

 

If I remember right you put everything together with a new crush sleeve with all the new gears, bearings...... Then once everything is together you take it all back apart and mic. the sleeve to see how long it is. Then take the new solid spacer and machine it to that exact size. Then put everything back together. The spacer since it is not crushable does not tend to move like the sleeve does, and allows a more solid position for the pinion gear.


Correct me if I'm wrong but I think thats how it works.

 

Sounds logically correct to me!

 

Couldn't you just measure the length of the old crush sleeve? No machining involved either, the spacer comes with shims to get the correct length.

You may want to do a search on this. I remember a few months back several members suggested getting rid of the crush sleeve/spacer all together and spot welding the pinion nut to the pinion gear. They claimed it was easier to setup this way and that the crush sleeve was only there to preload the pinion but to stop it from backing out.

 

The only purpose of the crush sleeve and/or solid spacer, is to keep the pinion nut from coming loose.

I set the bearing preload and then tack weld the pinion nut to the gear. It's easier than using a crush sleeve or solid spacer, and you're guaranteed that you won't lose bearing preload because of the nut backing off.

 

So they DON'T need to be machined? How would the shims work? Ya know, I don't understand why installing this spacer wouldn't be easier than a crush sleeve...I mean there should be only ONE measurement between the two pinion bearings...it's not like their distance ever changes...am I wrong?

 

If that's the case, then what is the point of getting rid of the crush sleave or using a solid spacer?

 

The only thing a solid spacer does is allow you to give the pinion nut more torque before you reach the proper pinion bearing preload. This makes it harder for the pinion nut to come loose, but as with a crush sleeve, it is still possible.

Toss out the crush sleeve, set preload, tack the nut, and you never have to worry about it again.

 

You’ve said that already.

If that was the only reason that the sleeve was there, then why get rid of it in the first place? Why would putting a solid spacer in there work? What would the point of running a solid spacer in there be anyway?

Lastly, pinion nuts have deformed tops to effectively make them a self locking nut, they don’t need any tension to keep them from backing off. If you find one that is not tightened properly then 95% chance it was never tightened properly to start with. Otherwise, it’s possible that it’s been reused too many times (you’re supposed to use a new one every time, but even if you don’t it usually won’t deform enough through a few uses that it will back off on it’s own). If it wasn’t for this design, you’d destroy bearings long before you could get enough tension by tightening against any kind of sleeve to keep a non locking nut from backing off. The tension needed to keep a nut tight is whatever is sufficient to stretch the threaded fastener less then it’s yield, which for something the size of the pinion would be a huge amount of force, much more then those little tapered bearings would take.

 

I don't really understand your question, or what you're trying to say. Do you have some other idea as to the reason a factory rearend has a crush sleeve, or why people replace them with solid spacers?

The factory crush sleeve is designed to resist tightening of the pinion nut before bearing preload is reached so the nut has a harder time coming loose.

A solid spacer (to be used in place of the crush sleeve) has the intended purpose of having even more torque applied to the pinion nut before reaching bearing preload.

The "self locking" pinion nut without the use of a crush sleeve or spacer would only require maybe 30 or so ft lbs before you reached bearing preload. With the use of a crush sleeve or spacer, it is approx 150ft lbs. So while you aren't 'stretching' the pinion gear at 150ft lbs, it is still a sufficient load to keep the pinion nut from loosening on a production vehicle.

I do not recommend using a crush sleeve or a solid spacer, so I'm not sure why your asking me what the point of running a solid spacer is.

BUT, as I have said before, with a crush sleeve, or a solid spacer, you still have the possibility of the pinion nut loosening. If you think it will not come loose because the nut is of the "self locking" variety, than good luck to you.

 

Please explain the process of this. What, do you just tighten the pinion nut, measure the bearing preload, and once it's @ the desired amount, simply tack weld the nut in a couple spots??

 

Yup, but only in ONE spot. Dont need anymore than that

mine is that way

 

I've used Ratec solid spacers with the "supplied" shim pack and I was very disappointed with the setup. The faces of the sleeve were not machined parallel from Ratec. This not only gave me fits with seating the Timkens squarely, It also threw the pinion yoke **** eyed. This in turn threw the U-joint way off center and was the major cause of a driveshaft vibration that I fought for a year. Never again will a Ratec sleeve touch my 12 bolt. I ended up using a two piece Strange all machined sleeve with a shim pack between the two sections. This was a much better system but I still wasn't real thrilled because the thinner shims would get kind of deformed under the high compressive and rotating loads seen during pinion nut torque down.

I haven't tried the tack weld idea but I like it. It will be way easier to set the preload (prevailing bearing torque) right on the button during setup. This will eliminate a couple of trial and error steps. Once you have the final setup and you're happy with pattern, just tack the nut. No more final disassembly to install the sleeve and hope you've still got the same preload.

Steve

 

I realize that I’ve sorta muddied things in trying to ask what I’m asking. Sorry.

Simply: a crush sleeve/solid collar will have no effect on keeping the nut from backing off. If it’s a good nut with good threads on the pinion it should not back off at all, if you’re worried about it, some locktight will go farther then the rather minimal amount that the crush sleeve does in holding it, but yea, the tack weld is probably less of a hassle.

So the thing is, what is that sleeve really in there for? If it is not there to set bearing preload, then there would be no advantage to using a solid sleeve. Also, if it did not effect preload then SABLT194 would not have had the problems that he described with his pinion.

My point being, either you’re missing the point of the crush sleeve, or I’m not understanding something here (If that’s the case, then the correct pinion preload without the sleeve would be different then with).

 

WS6,

A pinion is much like a front spindle. It has a rear bearing and a front bearing. Both of these bearings seat into a race, and a nut tightens the two bearings against one another. A front spindle uses a castle nut and a cotter pin to keep the preload. A pinion has no such thing. So, the factory used a crush sleeve to cause resistance against the nut from backing off. As was said, without the crush sleeve, the resistance is only about 35 ft-lbs. With the sleeve, the resistance can go over 100 ft-lbs. So, in order for the nut to loosen, it has to overcome 100 ft-lbs rotational torque versus 35 ft-bs.

So, the answer to your question is the crush sleeve does NOTHING for bearing preload. Bearing preload can be achieved without the crush sleeve, just as it is done with a front wheel spindle. It is two tapered roller bearings tightening against one another.

The main reason the factory used a crush sleeve is because welding the nut is a poor procedure if you ever want to rebuild the rear end, and reuse the old ring and pinion. I would imagine you would ruin the pinion trying to get the nut off. Also, solid spacers weren't a good idea for a mass produced housing that varied widely in spacer dimensions. So, the crush sleeve was an adequate fix for the problem of keeping the nut on.

Personally, I wish they would do it like the spindles are done. Drill a small hole in the end of the pinion and use a castle nut with a cotter pin.

The main reason the solid sleeve has become popular with some people, is because under VERY high loads (we're talking Pro Stock loads here), it is possible that the bearing preload could be overcome, and the crush sleeve would crush more than it was. After the load is removed, the crush sleeve is no longer putting preload on the nut, and the nut can back off. If the nut backs off, the bearings will loosen, and you are srewed.

Hopefully this explains it all a little better.....

Shane