Clank noise in tranny

I have a 2004 2500 HD 2 wheel drive with a 6 liter and 4 speed auto transmission. I have noticed that when I put the truck into reverse, the transmission will make a clunk noise just one time while I am rolling in reverse. It does not make the noise immediately when I put the truck in reverse. Sometimes it takes a few seconds to actually make the noise. You can feel the clunk when it happens. It feels like the transmission is popping into gear, but the car is already in gear and the car is already moving in reverse. Anyone else with the 4 speed auto transmission having this happen in reverse? Thanks

Here is the listing for bulletins. The driveline should be the same as the 2003. 2004 is not listed here yet. http://alldata.com/TSB/0311_mo.html.

C

I own a 2004 Chevy Silverado Crew Cab 4x4 and have the same problem, took it back to the dealer and the service tech said the noise was normal. He described it as the rear end "loading up". I tow a 20' bass boat and have noticed since I have now been towing for a few months, the noise has gone away.. or I'm just getting used to it and it doesn't register any more. Good luck.

both of you guys have the allison tranny correct? when your gears are turning forward in your rearend and the reverse there is a transition from the pressure coming from different sides. as long as its not consistent in reerse, its normal

My truck has the 4 speed automatic. The Allison is not available unless you go with the diesel or the 8.1. I have the 6.0 with 4.10 gears. The noise doesn't happen all of the time. If I am backing in reverse up my driveway which has a slight incline, I can almost always get the noise to occur. The noise doesn't happen right away. It happens after I am already in reverse and rolling. That is what puzzles me. If there is going to be a transition, it should happen right away when the truck is put into gear. Right? I don't know. I was going to ask the dealer at 3000 miles at the first oil change. That happens to be today.

hmmmm... have you checked your u-joints/driveshaft?

Just got back from the dealership. Had the oil changed and the service tech said that I do have the Allison. I have the 9200 Capacity 2500 HD and he said that they put an Allison in all of the 9200 2500HD's. He also said that the noise is inherent in the Allisons. I am still not convinced that I have the Allison. My window sticker says 4 speed auto tranny. He said that Allison makes the 4 speed. I always love the comment.........that is normal for that vehicle. I will research it more. The also do a 3000 mile underneath check for anything loose. Hopefully they looked at the driveshaft and U-joints. Thanks for your imput.
Anymore Clankers out there?