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.

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

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^^^^^

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: 66 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: 500 Likes: 348 Liked 233 Times in 62 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: 2,435 Likes: 774 Liked 699 Times in 203 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, 10:23 AM	#4
Alan Nyhus VIP Member Join Date: Dec 2002 Location: Lower Dakota territory Posts: 1,163 Likes: 1,013 Liked 761 Times in 225 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....."

10-11-2019, 11:54 AM	#6
gsa612 Senior Member Join Date: Jan 2008 Location: 100th Meridian Posts: 570 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: 403 Likes: 1 Liked 454 Times in 60 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.