GM 8.5 ten bolt crush sleeve

[Rory McNeil]

I was always under the impression that under load, the pinion is trying to push itself foreward, away from the ring gear. If this is true, the main load is directed to the much larger rear pinion bearing, which is pressed onto the pinion gear against a solid step or stop, which prevents the bearing from moving. If so, I really don`t see how the crush sleeve is under any extra load during launch, as the force is trying to push the pinion gear foreward, not to the rear, which would be putting force on the crush sleeve. I have seen several 9" Fords that had pushed the pinion support right out the front of the case, or broken the pinion support. I have never seen one that the pinion was pushed back inside the case. I have even heard of guys using NO crush sleeve or solid spacer between the pinion bearings. They said that as long as you had enough bearing preload on the pinion bearings, and the pinion nut was loctited or staked, the spacer was redundant. I`ve never tried it myself, but it does kinda make you wonder.

[Dragsinger]

Rory,

what you say is correct. I have in fact raced without a crush sleeve setup just as you describe.

However, I find comfort in installing the solid sleeve so the pinion nut can be "tight" Defining "solid" as a solid spacer with shims to arrive at the per-load you want.

You will find many opinions, I build up with VERY light pre-load. Without pinion seal I can "spin" the assembled pinion.

With my setup the pinion seal has about the same drag as my pre-load.

[Alan Nyhus]

I've never used a crush sleeve on any of the GM rears. A bit of red Loctite where the front pinion bearing locates on the pinion and a dab for the pinion nut is all I've ever used.

[SSDiv6]

Originally Posted by Rory McNeil

I was always under the impression that under load, the pinion is trying to push itself foreward, away from the ring gear. If this is true, the main load is directed to the much larger rear pinion bearing, which is pressed onto the pinion gear against a solid step or stop, which prevents the bearing from moving. If so, I really don`t see how the crush sleeve is under any extra load during launch, as the force is trying to push the pinion gear foreward, not to the rear, which would be putting force on the crush sleeve. I have seen several 9" Fords that had pushed the pinion support right out the front of the case, or broken the pinion support. I have never seen one that the pinion was pushed back inside the case. I have even heard of guys using NO crush sleeve or solid spacer between the pinion bearings. They said that as long as you had enough bearing preload on the pinion bearings, and the pinion nut was loctited or staked, the spacer was redundant. I`ve never tried it myself, but it does kinda make you wonder.

Rory,
You are correct on the physics on what takes places during acceleration.
However, the bearing cone will deform under load due to plasticity and move.

Got to remember the crush sleeve was designed for OEM applications and not for constant high RPM and/or high torque acceleration and deceleration with steep gears.
Also, the weight of the car and pinion angle have an effect too.

Also, most of the crush sleeves you buy, most of them are made overseas and you may question the materials used for their manufacturing.

One heavy stock eliminator that I am familiar with, it enhanced its gear life from once a year to five years just by switching to a solid spacer on a 8.5 GM rear end.

Like shared in an earlier post, I have seen crush sleeves collapse easily and seen others so strong that either cracks the sleeve or damages the pinion threads.

[Lou Jeffery]

The easiest way to understand the function of a crush sleeve or solid spacer is to compare it to front wheel bearings on a spindle.
Ever notice how little amount of torque it takes on the spindle nut to cause drag? Then we back it off slightly to give running clearance. That said our pinion bearings require NO running clearance they actually require preload that we measure in a torque to turn sequence. So we know that when we torque a nut pushing two tapered bearings together we cannot have much torque or the bearings go metal to metal and will not rotate.
Now we either install a collapsible steel sleeve called a crush sleeve or we install a solid shim spacer between the pinion bearings so we can achieve our torque to turn measurement and be able to have adequate pinion nut torque.
The crush sleeve although commonly misunderstood as being somehow inferior has one limit and that is the amount of torque it takes to yield and collapse. If it yields at 250 ft.lbs. that is the maximum torque able to be applied.
The solid spacer commonly used in Dana axles and now aftermarket applications has no limit because it is not compressible.
Either is suitable with the crush sleeve being Much less time consuming.
No matter what application, amount of load, RPM, pinion angle, brand etc. etc. The crush sleeve or solid spacer cannot be affected in any way until bearing failure.
One last thought " Inadequate preload causing gear deflection consumes more energy than proper preload drag"

[DIV3CR]

Is the 12 bolt solid spacer the same for the 10 bolt-8.5

[Mark Yacavone]

Originally Posted by DIV3CR

Is the 12 bolt solid spacer the same for the 10 bolt-8.5

No.
The 12 bolt goes from inner to outer inside bearing races.
The 8.5 (and the 7.5) seats against a shoulder on the pinion ,and loads the outer race only. The 8.8 Ford has a similar setup.

[MikeMoller]

Thanks for all the input guys.
The rear gears got installed today(thanks Doug Smith), elected to use the Ratech crush sleeve and it worked really well. Minimal effort to get the preload, if anything you need to be carful not to over tighten.

[henrys57wagon]

Originally Posted by Mark Yacavone

No.
The 12 bolt goes from inner to outer inside bearing races.
The 8.5 (and the 7.5) seats against a shoulder on the pinion ,and loads the outer race only. The 8.8 Ford has a similar setup.

Years ago I made solid spacers for 12 bolt's and when I was going to put an 8.5 in my HenryJ I looked at making a solid spacer but have it go from bearing to bearing. Went to a 12 bolt instead.