DragStuff

Is there any advantage/disadvantage to running a spacer instead of the stock crush sleeve in a 12 bolt chevy rear axle? I just receved my new 4.56 richmonds and Im ready to put them in and im not real crazy about the crush sleeve anyway so just wondering if anyone has used one of those spacers.

Thanks matt

Each time you launch, the sleeve has a tendency to crush a little more. IMO, ditch it and go with the spacer.

I ran a crush sleeve in my 12 bolt for years without a problem, BUT it was a foot brake car
I was advised and did use a solid spacer on the new car because it has a transbrake in it. It hits the rearend alot harder!

use the solid spacer ,it will take a little more time to set up,,,,but there is no chance it will change in dimension with loading.

Thanks guys ordered a spacer today.

Well to tell you the truth If you have the crush sleeve preloaded correct it should NOT crush any further considering it keeps the bearings from smashing themselves to hard into the races from both sides. SO...if it is loosening you either have the crush sleeve not preloaded enough from the beginning or bearing race wear problem... or your pinion nut loosened which is usually the main culprit of this problem. The torque twists so fast that the nut stays stationary for a spit second each launch and actually backs off. Reason for a new nut each time and lock tight... BUT even that fails, so we PEEN the nuts in place and they DO NOT back off.
Kind of think about it and it will make sense... If it makes you feel better go ahead and install solid crush sleeve. It will not hurt the rear...Just get it right on the money...Cause if you do not the pinion will wear the races and bearing to one side...The load side. or too tight and you will burn the bearings and races up. Over heating the pinion and SNAP!...

Good luck with it and enjoy the hobby even with the price of gas. Take care, Jim

Some of my bunch thought it might be the nut backing off, so we gave it the Lincoln treatment with a 6018 rod ( small tacks). Still happened, so we went to the spacers from then on. Our thinking was the sleeve kept crushing further from the shock of the torque being applied trying to push the pinion forward. We never had trouble setting up the rears until we starting getting over 600 rwh. Your expanation gives me reason to rethink the situation. It's habit now to do the spacer, so I never paid much attention to the original problem...

Yah if you look the way the bearings face each other on the tapers...no matter how much torque is delivered you should not be able to pull or push that pinion in or out. IF it is properly preloaded.
So either you have a bearing and or bearing cage giving way or out of spec. Or some one never got the preload correct in the first place. Was not truely seated to the correct preload.

I have heard people actually NOT even usuing a crush sleeve ...They preload the bearings and use a double jamb nut system... I am sure that could work and probably does. I will stick with the stock stuff as it has not failed us yet.

Setting up the rear diff still is one of the wonders of the auto mechanic business. Some can just get it right and some just do not pay the extra attention to the Job at hand...

I was just reading all the complaints about Moser and stranges rear making whining noises and grinding noises... on the Camaro LS1 forum. For that kind of money you would think that rear would be perfect. But you know Moser promises like 2 day turn around time etc. You have to wonder how much time is really taken on the set ups. AND considering the cars these rears go into 11 10 9 8 second cars what is a little noise right??? LOL. Bunch of BS.

We try to set every rear up as if It was going into my own car. If the rear takes a bit longer I will just call the customer and straight out tell them. I can slap it together and yes you will have the rear on time...But it will be WRONG! So I do not until I am happy and satisfied with it. I am human and I am sure It will happen some day... BUT till then... LOL.