DFI, Batch Fire, and other myths

[Greg Hermann]

>The way I know, the crush sleeve is only used to hold the inner bearing
>races against the pinion gear to keep the races from rotating relative to
>the pinion.  It doesn't take any gear loads.  You could remove the crush
>sleeve and loctite the inner races to the pinion.
>
>Gary Derian <gderian at cybergate.net>
>
Yes, you are right that it does not take any gear loads, Gary. But if you
put a really impressive torque on the flange nut, you will get excessive
pre-load on the bearings. I prefer the concept of pre-stressing the pinion
shaft in tension between the two bearing against a solid shim. Plus, if you
put any intermittent (stray) axial load against the flange (as this guy did
with a too long drive shaft), the sleeve will get loose pretty quickly.

Basically, I HATE them, think they a production shortcut, and that their
only redeeming social value is cost savings, and that they should be
removed at the first opportunity. Most serious racers would agree with my
position, I think!!

Regards, Greg
>>
>>Betcha it was a crush sleeve. The too long driveshaft pounded the companion
>>flange on the pinion into the sleeve hard enough to smush the sleeve beyond
>>where it was supposed to be, and the rest was history. No doubt the too
>>long shaft was what got the rear mount bolts too (before you fixed them!
>>
>>The crush sleeves are cheap for the mfgrs to use in a production
>>situation--beyond that they are not worth a #@$% !!!! For any performance
>>application, or even just for a quality rebuild, a conversion to positive
>>pinion preload shims is HIGHLY recommended for ANY rear axle!!!
>>
>>Regards, Greg
>>
>>