2004 2500 crew cab. I have a clunk when I shift into reverse and only reverse. It doesn't matter if you shift from park to reverse or from nuetral to reverse, it will still clunk. Nuetral to drive does not clunk. I did not feel any play or slop in any of the u joints. I did lay under the truck while my wife put it in reverse, and it sounds like it is coming from the front driveshaft/ carrier bearing/ transmission tailshaft, but not sure of which. any suggestions would be greatly appreciated.

 

this may sound kinda silly but have you checked your tranny fluid? If so than when you shift from park or drive, are you moving? I know if you park on a hill and don't use the e-brake than you will hear a loud clunk. Hope this helps, good luck

 

I have not checked the tranny fluid. The truck is parked on a flat driveway, with foot on the brake, shifting into reverse and holding the brakes, I can hear a somewhat loud clunk. Moving on to nuetral and into drive, no clunk....but moving back into nuetral and then into reverse, I get another clunk. In case it matters, this is on a 2004-2500 crew cab 4x4.

 

i know that gm set up the main drive shaft to have a certain amount of play in the u joints. i have a 2004 1500 4x4 that does the same thing. i've taken it to the dealer and it has always been to spec.

 

I would suspect U-joints but it could also be that the drive shaft splines are dry, do you get the infamous clunk when you come to stops?

 

I have not noticed any clunks when I come to a stop, only when it is shifted into gear. I checked the trans fluid and it was a touch low so I added about 1/2 to 3/4 of a quart of regular old ATF with stop leak. Is this going to cause any problems? I never gave it any thought as to a specific kind of ATF. I was under the truck again tonight and it sounds like the noise is coming from the u joint at the transfer case or possibly the transfer case itself. I'll start with the u joint first.

 

drive train clunks are typically caused by slack in the drive line and the U-joints are most likely the cause.

 

i get the clunks when i come to a stop will that be the U joint? its been doing it for a few days now. i havent had a chance to get under the truck since i dont have time much to do so but i wanna see if i may get any suggestions and maybe i could try and do it some day soon..

 

it could be but most likely clunks that come when you stop is a dry spline shaft..
check out this link for lubing the drive shaft splines....

http://www.truckmodcentral.com/forum...ead.php?t=2504

 

thank you hope this actually works for me. will keep try and keep the post updated.