howling differential

[Realest]

Hey Guys,
I know this question is non a-body related and not even mopar but I couldn't think of anywhere else to give me an accurate and quick answer. I have a howl in my 1994 GMC K1500 4x4 starting at about the speed of 50 kilometer per hour up to 100ish. Soon as you let off the throttle the howl goes away. Couple summers I had changed the fluid to S75W90 and this fall i started getting a howl. So I changed the fluid back to dinosaur gear oil (80w90). When I was in there I took a quick look at the crown and didn't seem very worn. (260 000 km on the truck)
So...I believe that the side bearing of my carrier are most likely worn as I don't have an play up/down or in/out of my pinion. I want to go in there this week, yank the axles (replace wheel bearings and seals while in there), yank the carrier and replace side bearings.
What kind of backlash should I be aiming for? I was thinking .006" to .010". What do you(s) think?

Thanks in advance,
Ryan

 

[catsncudas]

Specs are .005-.009 backlash. I'd check the pinion bearing while you have it that far apart. I've replaced quite a few of those. If you have to replace them, the preload is 24-32 inch lbs.

 

[Realest]

thank you for your reply
i think i will do the pinion while i am in there.
a diff bearing kit was only 100 bucks came with crush washer, a selection of various pinion seals (two or three), wheel seals, and all bearing cones and cups.

 

[Realest]

Well I replaced all the bearings in the rear axles tonight, set the preload to 25 in lbs on my pinion, and my back lash measured out at .008". I am happy to say the howling is gone. All seals were replaced too, will have to inspect tomorrow for leaks.