Front Differential Bearing Noise!!

[mikelawson]

I just purchased a 2002 TB and have been a little shocked by the number of problems on this model year. I understand that it was the first year and all. but I am hoping this will not come back and bite me in the **s! Anyway, I have a "tire/wheel bearing" noise coming from the front end at speeds over 35. I replaced both wheel bearings thinking this was the problem, but it didn't change sound at all. The noise does not change depending upon road surface, so I am eliminating the possibilty of it being tires as well. I did notice the tie rod ends have too much play in them and have ordered new ones, but I honestly have never seen this make a wheel bearing noise (I'm leaving the possibilty that the tire could be wobbling back and forth while I'm holding the wheel straight from the worn tie rod ends). I believe (but hope not) that it may be coming from the front differential bearings. Does the diff. have to be dropped to replace the drivers side bearing or can you pull the axle and get to it from there somehow? Any help or ideas would be great. This is an LT with 82000 miles. Other than a fan clutch (of course) this truck is immaculate and was a good buy for only $9500.

[ScarabEpic22]

Have you changed the front diff fluid to synthetic 75W-90? Any good synthetic diff oil works, and most you can use for both the front and rear.

That should be done anyway, and if you dont know if the transfer case fluid has been changed order 2L of AutoTrak II fluid next time you are at the dealer (only fluid that works for the TC, no aftermarket fluids meet the GM specs).

Other than that, what mode of 4WD is it occuring in? Like only A4WD, 4HI, etc? If it is in all of them, I have no idea, Im just trying to figure out the operating parameters of when it makes the noise.

[mikelawson]

Thanks for the quick response. I have yet to change any fluids, but plan to do that within a few weeks. Will probably do AMSOIL or LUCAS. It makes the noise regardless of whether it's in 4wd or 2wd. It sounds just like a pickup truck with 33" mud tires. Hopefully it's something easy.

[eckvoys toy]

just change the fluids almost guarentee that will work at least it did with mine i had the exact same problems..i was ready to sell it back i made a stink bout it on here lol

[mikelawson]

Thanks for the info! I will change it out for synthetic Lucas tomorrow to see if that will eliminate it! I agree it needs to be done regardless! I will follow up tomorrow with the result.

[MTPockets]

Did you check the oil level in the front diff? If it was run low on oil, or you find shavings [from being low on oil], she's toast. The diff has to be dropped and the case split to changeout the drivers side output bearing. The pass side is bolted to the engine oil pan and can be replaced with the diff in place. If you find shavings, I'd just get a whole new/reman'd diff assembly. Unfortunately, it will probably be as much as a remand transmission.

Joel

[MichEnvoyBoy]

Well my 02 Envoy had 90,000 miles on it when my front passenger differential bearings needed replacement :crazy: It wasnt a bad job, however the CV axle from flopping around because the bearings were literally GONE, had chewed up the differential housing so I had to replace that too. That was the PITA of the whole job. The housing was on backorder and had to be ordered from a dealership out of state.

Heres the original thread with my problem:
http://forums.trailvoy.com/showthread.php?t=15450&highlight=front+differential

FWIW, I think the design on the front passenger side of the differential sucks. Basically GM slaps a tiny bit of grease into this huge housing with some rather important bearings and there is no required checkup or maintenace on it. I made sure when I repaired my front differential I repacked it with synthetic grease and I will make sure to inspect it now at least every 15,000 miles!

[mikelawson]

I just replaced the diff fluid with Lucas 75w90 synthetic and it didn't help any. I didn't see any metal shavings, so I don't think I have damaged the housing, but I need to find the problem before something goes. I saw where the pass side is bolted to the oil pan. I'm hoping that's the bearing that is shot. Assuming you didn't have to replace the entire front diff, would only replacing the pass side bearing have been fairly easy? Thanks for the link MichEnvoyBoy, it was helpful. I'm a little worried about the axle through the oil pan. Am I going to need a special tool to pull the front pass axle shaft out once I get it disconnected from the knuckle, or will it come out as an assembly if I unbolt it from the pan?
Thanks for the info everyone.

Mike.

[MichEnvoyBoy]

It wasnt hard to replace the right side differential bearings, just more than I expected. I thought I had a bad CV halfshaft. Do this:
Go down and grab the inner side of your passenger half shaft. Yank on it from side to side and up and down (stop laughing.. I know it sounds perverted but its not meant to be) :D My passenger half shaft had about 1" of movement in all directions indicating there was no support from the bearings. In fact, the bearings were non existant once I got things apart :eek: Nothing left to them at all and i missing a whole bunch of bearing housing.

[Trailblazin]

im getting alot of noises from mine front axle now.. it sounds like im dragging a cardboard box underneath my car, only happens when im moving... am i gonna have to do a whole rehaul of the front axle??

[the roadie]

im getting alot of noises from mine front axle now.. it sounds like im dragging a cardboard box underneath my car, only happens when im moving... am i gonna have to do a whole rehaul of the front axle??Only way to tell is put it on a lift and turn the wheels by hand - see what's the noisemaker: axles or differential. That's such bad luck to do all that work to lift it and play in the sand for such a short time. My sympathies.

[mikelawson]

Well, I climbed under the truck and I cannot move my axles much at the differential. I am going to have to pull the axles one at a time and then drive the vehicle to see if the noise has been eliminated. Anyone see any problems with trouble shooting like that?
Mike.

[Gm Tech2]

There is a number of problems with the front diffs Porous housings bad bearings if you want more info let me know -I'm new to this so I'm not sire how this all works.

[joe_jeep]

the half shaft center nut is torqued to put preload on the wheel bearing. it is bad to drive on a bearing with out the preload. it will laterally stress the bearing and it will fail quickly. plus with out the shaft it will leak diff fluid wont it? most tricks would. with the weird axle under here perhaps it wont but most do!