pinion nut loose
 

Hi All ! Chevy 12 bolts , solid sleeve ( MW #58905),ritchmond gear 5.57, new pinion bearing . Rotating torque 25 inch pound,.New Gm nut ,Pinion come loose again . What going wrong?
Any input welcome!

Re: pinion nut loose
 

How much did you torque it to? They need about 250 ft lbs.

Re: pinion nut loose
 

Pinion nuts are really designed for one time use only ,if it was not tightened enough the first time and came loose ,it should be replaced. .
Even though they are a prevailing torque locking nut , I always red loctite them.
225-250# with a solid sleeve.

Re: pinion nut loose
 

Check that the washer is seating correctly in the pinion flange and that it's thick enough so the nut isn't bottoming out on an unthreaded portion of the pinion. I had one set where the pinion threads stopped about .250 from the splined portion of the pinion.

Those solid spacers can fake you out on bearing preload. I don't use any spacer or crush sleeve...just a little red Loctite on the pinion where the front bearing locates. If the pinion flange fit on the pinion is a bit sloppy, red Loctite or a couple of peens on the pinion nut can help.

Hope this helps. -Al

Re: pinion nut loose
 

Exactly this^^^^^

Re: pinion nut loose
 

What I do on mine is grind a V on the start of the pinion thread,set preload,and then stake the nut into the groove.No spacer or crush sleeve.Never had a problem...gsa612

Re: pinion nut loose
 

Maybe I'm doing it wrong, but using a solid bearing spacer I torque my MW nut to 250+/- with an electric impact. I then fill the void between the nut and the yoke with Permatex Ultra Grey. I have been doing my own 12 bolt rear ends for 15 years, and never had any issues (R&P or otherwise).

It does however take some time to dig out the Ultra Grey when it is time to remove the pinion gear.

Re: pinion nut loose
 

Yes I torque 250 ft lbs. !