Bearing Preload Question - Please Help !!
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From: Billings , Montana
Bearing Preload Question - Please Help !!
I don't want to be breaking some cross-posting rule but I really need an answer and with the depth of knowledge here cannot believe someone doesn't have a answer.
I have a rear-end whine during decel. Reading through the threads:
How to replace pinion seal 2004-2008
https://www.f150online.com/forums/20...04-2008-a.html
Pinion flange torque? 9.75
https://www.f150online.com/forums/20...ue-9-75-a.html
and others I think I have a fairly good understanding of the problem.
My question is if I check the preload now as outlined in the threads above
and it is lower than (8-14 in lbs -used) can I carefully tighten the pinion nut
to bring it up into the proper range. Could this correct the problem and stop
the whine?
In a (maybe) related problem I may not have put the driveshaft back in the
same position on the pinion shaft flange when I replaced the u-joints awhile back. The book (Chilton) says the driveshaft has to be returned to the same place to maintain the "dynamic balance" of the driveshaft. As there are only two ways (4?) for the driveshaft to bolt up how do I pick the right one to restore the balance?
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I have a rear-end whine during decel. Reading through the threads:
How to replace pinion seal 2004-2008
https://www.f150online.com/forums/20...04-2008-a.html
Pinion flange torque? 9.75
https://www.f150online.com/forums/20...ue-9-75-a.html
and others I think I have a fairly good understanding of the problem.
My question is if I check the preload now as outlined in the threads above
and it is lower than (8-14 in lbs -used) can I carefully tighten the pinion nut
to bring it up into the proper range. Could this correct the problem and stop
the whine?
In a (maybe) related problem I may not have put the driveshaft back in the
same position on the pinion shaft flange when I replaced the u-joints awhile back. The book (Chilton) says the driveshaft has to be returned to the same place to maintain the "dynamic balance" of the driveshaft. As there are only two ways (4?) for the driveshaft to bolt up how do I pick the right one to restore the balance?
__________________
Yes, you can tighten a set pinion nut to increase bearing preload. Yes, this will fix a whining differential, if it's caused by a pinion with not enough preload. The risk just comes from going too far, and then having to tear apart your differential to start over. Turn the nut in ~1/8" increments and check the preload every time.
I wouldn't substitute this method for new parts, but because I don't know the service history of your truck, I'm just gonna assume you aren't putting a band-aid on a bullet wound.
If you forgot to mark the driveshaft/yoke/pinion flange before you did your u-joints, you're pretty much left with 8 possible reassembly combinations on that side. If it was really far off, you'd only end up with vibrations, not a whining sound.
I wouldn't substitute this method for new parts, but because I don't know the service history of your truck, I'm just gonna assume you aren't putting a band-aid on a bullet wound.
If you forgot to mark the driveshaft/yoke/pinion flange before you did your u-joints, you're pretty much left with 8 possible reassembly combinations on that side. If it was really far off, you'd only end up with vibrations, not a whining sound.
Last edited by AndersonS; Jan 25, 2013 at 12:37 AM.
Senior Member
Joined: Jul 2004
Posts: 6,200
Likes: 39
From: Easton, Pa.
If you had the ring an pinion apart, the whine is likely due to the existing pattern between the ring gear and pinion.
If a small change in preload does not do it, it's back to square one.
Good luck.
If a small change in preload does not do it, it's back to square one.
Good luck.