pinion nut loose

Weekend Racer · 10-11-2019, 09:19 AM

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!

John Dinkel · 10-11-2019, 09:46 AM

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

Tom Goldman · 10-11-2019, 10:21 AM

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.

nhramnl · 10-11-2019, 11:51 AM

Quote:

Originally Posted by Tom Goldman

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.

Exactly this^^^^^

Alan Nyhus · 10-11-2019, 10:23 AM

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

gsa612 · 10-11-2019, 11:54 AM

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

Bill Grubbs · 10-11-2019, 12:45 PM

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.

Weekend Racer · 10-11-2019, 03:31 PM

Quote:

Originally Posted by John Dinkel

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

Yes I torque 250 ft lbs. !

10-11-2019, 09:19 AM	#1
Weekend Racer Junior Member Join Date: Feb 2003 Location: P.Q. Posts: 68 Likes: 1 Liked 1 Time in 1 Post	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!

10-11-2019, 09:46 AM	#2
John Dinkel Senior Member Join Date: Nov 2005 Location: Pinckney, Michigan Posts: 507 Likes: 399 Liked 263 Times in 68 Posts	Re: pinion nut loose How much did you torque it to? They need about 250 ft lbs. __________________ John Dinkel 3295 STK

10-11-2019, 10:21 AM	#3
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,473 Likes: 882 Liked 858 Times in 234 Posts	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. __________________ Tom Goldman 1500 SG , 1506 STK

10-11-2019, 11:54 AM	#6
gsa612 Senior Member Join Date: Jan 2008 Location: 100th Meridian Posts: 569 Likes: 116 Liked 280 Times in 139 Posts	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 Last edited by gsa612; 10-11-2019 at 11:58 AM.

10-11-2019, 12:45 PM	#7
Bill Grubbs Member Join Date: Oct 2002 Location: Magnolia, Texas Posts: 416 Likes: 3 Liked 564 Times in 66 Posts	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.

10-11-2019, 10:23 AM	#5
Alan Nyhus VIP Member Join Date: Dec 2002 Location: Lower Dakota territory Posts: 1,180 Likes: 1,074 Liked 799 Times in 236 Posts	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 __________________ "That'll never work....."