Rusted out trans oil lines and dif howl

[pretz99]

I bought a used 02 Tb before I found this forum (major ooops). One week after I had it the trans oil cooler lines rusted out at the first bend and blew oil everywhere. The dealer said that was weird, never seen oil lines leak like that and then proceeded to charge me full price (since the warranty is off).

My rear end dif has quite a howl when I accelerate, and the dealer (same) says it is not a big deal. Is it o.k. to put some heavier oil in there?

Thanks

[tom3]

Probably wouldn't hurt to put in a heavier multiweight gear lube, but what I've seen over the years, won't do anything for the noise. You have a bad gear match in the ring and pinon, not unusual but sure a nuisance. Sounds like you might have gotten a really well used TB, maybe an early lease vehicle. Hope you have better luck with it than the initial impression

[GMMerlin]

Originally Posted by tom3

Probably wouldn't hurt to put in a heavier multiweight gear lube, but what I've seen over the years, won't do anything for the noise. You have a bad gear match in the ring and pinon, not unusual but sure a nuisance. Sounds like you might have gotten a really well used TB, maybe an early lease vehicle. Hope you have better luck with it than the initial impression

Using heavier lubercants can cause problems..sometimes thicker is not better.
This is what you should be using SAE 75W-90 Synthetic Axle Lubricant (GM P/N 12378261, Canadian P/N 10953455) or equivalent meeting GM Specification 9986115.
As far as the noise you hear, if it is happening on or during acceleration the most likley cause ia a ring and pinion concern (misadjusted backlash or worn gearset)
If this noise is all the time and changes with speed, I would look towards a bearing problem

[auburnwoods]

Originally Posted by GMMerlin

Using heavier lubercants can cause problems..sometimes thicker is not better.
This is what you should be using SAE 75W-90 Synthetic Axle Lubricant (GM P/N 12378261, Canadian P/N 10953455) or equivalent meeting GM Specification 9986115.
As far as the noise you hear, if it is happening on or during acceleration the most likley cause ia a ring and pinion concern (misadjusted backlash or worn gearset)
If this noise is all the time and changes with speed, I would look towards a bearing problem

I've been having the same issue with my 2002 TB and found this forum to discuss a solution. The humming/droning/moaning noise coming from the rear of the cab is not from my tires because I get the same sound on the new set as the old. This sound only happens at a certain RPM and speed combo. At 50 MPH and 2000 RPM (holding at that rate) it happens and at 70-72 MPH and 2000 RPM (holding at that rate) it happens. I drive 60 mi round trip to work each day, mostly freeway @ 65+ MPH. I have already changed the diff fluid using the synthetic 75W-90 Mobile oil and the sound got quieter, but now it's returning and it has only been around 3000 mi since I changed it last. When I did change it @ 50,000 the oil was thick, greyish, and smelled something fierce. Anyone have any advice I what I sould try next or should I take it to a repair shop and have the gearset checked. Thanks for your help

[tom3]

Heard of this in several TBs. Seems the rear springs have a harmonic frequency that creates this noise. Dealers were replacing these springs under warranty for a while, probably cost you for this now. Might research in this direction some. Get you started:

http://www.mytrailblazer.com/shared/...2&REPLYCOUNT=3