My 2004 SLE 4x4 1/2T has been fine EXCEPT for the clunking noise in the auto transmission when shifting between 2nd and 3rd and sometime between 3rd and 4th. Truck is smooth and quite EXCEPT for this ANNOYING noise!

Dealer says this annoying noise is "normal" :banghead: according to GM in order to improve gas mileage ( :rofl: ) but the problem is NOT consistan; it just occurs 8 or 9 out of 10 times when it shifts.

I also intermittently expirence a "slipping" of the clutch when taking off from a stop light.

Does anybody else expirence these problems too?

I've never had any problems like that in my 03, and while test driving many other trucks (anywhere between 01 - 05 I've never experienced anything like that (In either the allison, or the regular tranny). It definately sounds like something is wrong (I just don't know what). My guess is the dealer doesn't want to give you any warrantee work if he doesnt have too. Try telling them the tranny lets go completely upon accelleration sometimes. They'll have to give the truck a look.

Just a thought about dealing with the service people at your dealership. Try taking your truck to another GMC Dealer and have their mechanics check it out. Your new vehicle warranty is honored at all GMC dealers. Good luck, it does sound as if they don't want to do the service work.