Pinion nut loosening

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CCHHAARRGGER!

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Anyone have a problem with the 8 3/4 pinon nut loosening up. I just re torqued it to 20 Ft PDS, Ill see if i holds . Never had this happen before. 2nd time its come loose after an engine swap since July.
 
I thought the pinion nut required a couple hundred ft/lbs torque. What casting number do you have?
 
Casting is 741. The only specs I could find said 15-25, which seams light to me since they have always been a pain in the rear to remove. BTW, I also removed the nut about a year ago to replace the pinion seal . Its Possible I am not tightening enough.
 
15-25 ft/lbs is the pinion bearing preload spec. That doesn't mean anything once the diff has been setup, used, etc. You need to tighten the pinion nut to 240 ft/lbs if I remember correctly! Its very tight, i hammer on it with an impact and call it good on my car. Hopefully your bearings and gears aren't messed up.
 
That is the rolling torque of the pinion. Better consult the manual again.
I believe you need to pull axles to get proper rolling torque.
Loose pinion nut will result in catastrophic failure...
 
1994redram said:
15-25 ft/lbs is the pinion bearing preload spec. That doesn't mean anything once the diff has been setup, used, etc. You need to tighten the pinion nut to 240 ft/lbs if I remember correctly! Its very tight, i hammer on it with an impact and call it good on my car. Hopefully your bearings and gears aren't messed up.
Click to expand...

Ok thanks. I appreciate it. As soon as I heard noise I stopped driving it . I checked the bearing and its still good. Luckily I can hear when it loosened up.
 
Do what Toolman said along with Red Locktite. 741-742 have no crush sleeve so tighten away. 489 case is another story.
 
You can tighten it up to 240+ and then take a punch and peen the top of nut to distort it slightly. Might help with it backing off.
 
I always use red lock tite and stake the cat piss out of the nut to the pinion shaft.
 
its a self locking nut! needs to be replaced with new locking nut any time its removed! has a plastitc ring in it the threads cut into to lock it and reusing is not advised and all the loctite in the world ant gonna hold it! went threw it on a 71 duster years ago! when the pinion bottoms out into the carrier at a 7800 rpm 1-2 shift bad things happin!! go by a self locking nut and save the aggravation!
 
dirty white boy said:
its a self locking nut! needs to be replaced with new locking nut any time its removed! has a plastitc ring in it the threads cut into to lock it and reusing is not advised and all the loctite in the world ant gonna hold it! went threw it on a 71 duster years ago! when the pinion bottoms out into the carrier at a 7800 rpm 1-2 shift bad things happin!! go by a self locking nut and save the aggravation!
Click to expand...

If you've had problems with red lock tite not holding a pinion nut, you're doin it wrong.
 
RustyRatRod said:
If you've had problems with red lock tite not holding a pinion nut, you're doin it wrong.
Click to expand...
tried it twice with red locktie an a 3 foot pipe on 1/2 inch ratchet and in a day or 2 it was lose again, put new lock nut on it with big impact wrench and far as i know was still tight 9 years later when i traded it! threads was wore out in the nut probably why the locktite didnt work, im still a ferm believer in a new lock nut tho!
 
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