Differential noise - bearings?
 

Hey guys,
Been awhile. Starting playing with the car a bit more - now I'm back to the truck.
Truck started making a whining noise around spring '07. I chalked it up to the tires not getting rotated often enough and getting irregular wear. It got progressively a bit worse, and figured I would have to replace the tires, but didn't want to replace 1/2 worn tires. So I lived with the whine.
The noise makes itself known around 20mph, gets really loud (whole cab resonates it seems) around 40mph, subsides past 55mph and almost disappears at 70mph.
Fastforward to sept '07 when I took a diff sample (didn't get it to blackstone until feb 08, lazy). See the results attached, elevated iron. Blockhead me didn't make the connection.
Today got new tires. Noise still there. ARG :-banghead. Jacked up the back of the truck, started it and ran the speedo to 20mph - same noise.
From searching the forums it seems like the bearings. That's what I'm going by.
Here's the kicker - leave tomorrow for a trip pulling the camper, get back in a week. Truck has been on about 12 towing trips since the noise showed up. I'm thinking it will be okay for one more trip before I get it to the shop. BTW I changed the diff fluid about one month ago. Noise hasn't gotten worse for months.
Thoughts? Is this caused by bad preload on the bearings (assuming it's bearings)?

Thanks...

I know the whining sound isn't a good thing, sounds like the rear for sure. I,m no expert but those iron numbers don't sound good at all. I'll be watching this thread for sure, good luck. Bump....

I just had my diff bearings replaced TODAY. I had a new pinion seal put in about 8 months ago, then again about 1 month ago, then about 2 weeks ago, it started whining / whirring and I pulled the fill plug and found a ton of metal shavings on it. This time I took it to a differential shop, and they said the bearing(s) have probably been bad for the whole time and that's why the seal went out twice. Said the two guys that replaced the seal should have replaced the bearings at the same time (most recent was a Ford Truck dealer). Anyway, it was about 500 for new bearing kit, new oil, and labor. Now it should be done, and good for another 100k miles...

Just outta curiousity, what kind of gear lube have ya been using, what vis. rating? I find the silicon values intersting. hmmm, As far as your trip goes, that's a hard one, I personally think I'd be postponing. few things suck as much as sitting along side the highway in the middle of no where, exspecialy with a trailer on! sure would suck to throw something out as 65-70 mph, lock everything up and start to skid those brand new tires, jacknife the trailer, or send a piece of gear through the pig! I think I'd opt out of that trip, ole' buddy.

I had that problem - Rear Main Bearing (Cheap repair). But then again - alot of things could be rubbing and making noise back there. Just a possibility

Was using Valvoline synth 75w-140 I believe (whatever was spec'd in the manual). Switched to Royal Purple about a month ago.

When I changed, very little metal in there at all, looked normal. I think I am going to call my stealership tomorrow and see if I can fit in (fat chance but thought I'd try).

We will see...

Folks, you can take this for what it's worth. In eastern ky, I work on a lot of coal haulers. The manufactures have been going with synthetic gear oil from the factory for the past several years. The coal haulers have found out that regular petroleum gear oil, the higher the viscosity, the better, works best for them. They push their trucks to the limit and some. So, if you're running heavy, you might want to consider switching to regular petro gear oil as a possibility. Personally, I like synthetic oil, but this is what the coal haulers have told me.

probably bearings (as long as the gears were setup correctly) but dont drive it too much b/c with the bearings out of wack that can affect the gears which could become costly
if the bearings have to be replaced now would be the time to add a limited slip or a locker if you have wanted one

Hey guys,
Went on the trip and made it back fine, nothing blew up. Noise still there of course.
Got it into the dealer today and got the verdict - I need some new bearings (carrier I think). I also had a shuddering problem around corners - need a new clutch pack for the LSD. And while they're in there, the rear pads need changing and the rotors resurfaced. About $2000 total. There goes my stimulus check and then some (except I spent it already)!
Stinks to fork over the money, I knew I probably could have gotten cheaper from someplace other than the dealer, but I just don't know of any good shops around. At least I'd been able to get a lot of good advice and free diagnostics out of these guys, makes it a little easier to "digest."
Thought ya'll would like to know...

Appreciate the update. Let us know how it turns out once it's done.

Glad ya made the trip there and back O.K. That sure is a lot of dough but now it should last ya as long as the truck does. Talk to ya later...

All done and back from the dealer - just a shade under $2k. Apparently they changed all the bearings while they were in there. They also apparently didn't charge me for the new rear pads and rotor turning (although it was done, e-brake has less play) so that was nice.

And most important of all, NO MORE NOISE! :)

Well besides the charge, glad everythings back to normal. I changed my diff. fluid out 2 weeks ago with the 75-140 R.P. and no friction modifier. Don't have any scuffing around corners or binding but had to add a little just recently. I,m wondering about the metal shavings though, not big but still getting on the plug, any thoughts? Is this just what i couldn't clean out?