what is a crush sleeve? how does it work? what torque?

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what is a crush sleeve? how does it work? what torque?

Post by monzaz » Wed Mar 25, 2009 10:48 pm

Ok well there is NO torque for the pinion nut per say...

Lets start with the crush sleeve.
The crush sleeve is between the inner and outer pinion bearings. The sleeves job is to keep the pressure outward against the two bearings. The crush sleeve as in its name is to be crushed upon final differential assembly and keeps the bearings pressure consistent in the bearing cups.

NOW the Nut at the time of assembly will take 100-180 FT Lbs. (depending on the size of the sleeve ) to crush a crush sleeve to the point at which the bearings are seated into the bearing cups/races. At the point of contact by both bearings into there matching races/cups you will start a pre-load pressure into each other...this is usually a inch pound measurement and about 20-25 or a slight drag by hand with NO RING GEAR installed.

SO the torque rating on the pinion nut will depend on the type and size crush sleeve you have...but the rating is just what it takes to actually crush the pinion crush sleeve. It may only take 80 on a 8.5 and on a 12 bolt it may take 200 ft lbs. just because it has a thicker heavy gauge metal sleeve to crush.

The pinion nut new is usually pre crushed locking nut and sometimes oblong ...but we also use lock tight and I personally stake the nut to the thread with a punch and hammer for performance applications.

NEED to replace a seal and reinstall yoke....

Amount or torque to re install the yoke etc. Just tighten the nut tight as you can with holding the yoke ...you can hold the yoke with a large monkey /pipe wrench. IF the the nut tightens to the point at which you have a tough time turning the pinion you will need to replace the crush sleeve. Bad news here, you will need to re remove the seal yoke and the outer bearing...at least on a 8.5 this is a job that can be done from the front and the pinion in tacked. Other rears like the 12 bolt and 10 bolt chevy you need to remove all of the guts.

If the pinion feels good like it did before disassembling or slightly tighter but still smooth you are good. STAKE that pinion nut in 2-3 spots with a pointed punch into the pinion thread and let it be.

I am sure there will be some comments to this so I am just being realistic to what you can do with what you have.

Any shop will just tell you ' oh you need to buy new crush sleeve and a inch pound torque wrench ' and so on.

Good luck with the diff. Jim
J D Race

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