Guys, i have been trying to track down a clunking noise underneath my truck for a liitle while now.., I thought it was my U-JOINT, but i laid under the truck and found that if i turn my front drive shaft side to side, It makes the small clunk noise in the T-CASE. Is this bad? Why does it do this??? , Truck has 39,000 miles and I have been easy on the 4x4 system.

 

I've seen this problem before and every GM dealer i've talked to said its "normal" which I still believe is total BS but i haven't seen any damage as a result of it. Typically i've seen it in the 99-02 NBS trucks such as mine.

 

Maybe easy on it when in 4wd, but I'm sure in 2wd you haven't. The shaft still spins. You might want to make sure it's not the front driveshaft u-joints.
The dealership will tell you it is normal. My brothers truck did the same thing.
After the t-case was rebuilt, the clunk went away. Go figure.

Jim

 

your right, i like to romp on it in 2 wheel. Do you think my t-case will fail or just clunk around every now and then till i get it some attention? I also found driving with tow/haul mode it didnt clunk , it mostly clunks when it goes from a mild 2-3 shift or when it kinda "lags" at part throttle in 3rd gear at low speeds. I think my u-joints front and rear are ok. but how do YOU check them? I dont notice any play or squeeking when i rotate the front drive shaft by hand.

 

I owuldnt worry about it tim mine does it too and has done it for 70K. I have done MANY 4wd launches with nitrous and all the other BS and given it hell offroad. My truck has also seen many loads pulling 10K trailers up into the mountains in Tennessee in auto 4wd and 4hi with no problems. Last time I put it in 4wd it worked fine and thats with close to 190K on the ticker. Unless the t-case starts whining I wouldnt worry about it.

 

Cody, THANKS A MILLION!!! Im glad to hear that this is kinda a normal thing . I just rebuilt the rear end and didnt want another week of downtime! If the case can last in your TQ monster, surely it will be alright in mine But it still is annoying, I think i drive a nice truck that ive dumped serioius cash in and when she clunks it pisses you off.

 

I understand for sure. Im buying a whole drivetrain out of an 03 2500hd soon so when the trans/t-case/rear end/or motor goes out Ill have a replacement. All the towig occured with the 5.3 but I did spray it quite a few times while towing(not a bright idea but oh well) to get out around people on the mountains I think thats what killed my TCI converter. You can pick up an autotrac t-case for around 4bills if need be and its and easy swap, would take maybe 4 hours for someone who hasnt done it before.

 

My brother got his t-case totally rebuilt. It was so badly worn, the fluid was running out of it, and the chain inside was dragging in the case. It was rebuilt for $1700.00 and came with a 3yr/ 36,000mi warranty. GM's rebuilt unit can't nearly compare to warranty. 90 days............wow.
The guy that rebuilt his tranny is in Houston. That's pretty much all this guy does, rebuilds t-cases and differentials.
4-wheel parts sends all their customers that need t-cases rebuilt to this guy if that means anything.
I don't know the name of the shop though. My brother may still remember.

Jim