twist driveshaft when stopped. if it moves excessively it either needs to be greased or u-joints replaced.

 

Mine was doing the same thing until I dropped my driveshaft and lubed the splines. Hope this helps!

 

Drive shaft splines.

 

mine does the samething ive greased the splines and it still does it i cant seem to figure it out hope you can find yours if so let me know what the cure was.

 

Will grease the splines tomorrow, I'll let you know if it works. Thanks guys.

 

Check you cross member bar & the lift components in the area. Mine did the same thing. A few bolts were loose making it shift.

 

My dad had a 2500 Sub a few years ago with this problem. Stealer replaced the rearend 3 or 4 times before lemon lawing it. Each time they said the oil was contaminated. My dad does a lot of mountain driving with a lot of long turns. They speculate that this caused the rearend to lock and unlock constantly causing undue wear to the diff components creating the clunk. If it's not the driveshaft, you may want to check the rearend.

 

Check the body mounts, too. GM had some problems with them making a clunking sound. My moms tahoe had it. Just another sugestion.

 

Not familiar with that lift, did you replace the springs or is it blocks in the rear? You may want to check the install for tightness there maybe something loose or it could be axle wrap. Some people have reported that the spring leaf spacers coming out. I also had a situation where the spare tire was loose on my 96 2500HD everytime I would start out it made a clunk. Just a thought.

 

Not familiar with that lift, did you replace the springs or is it blocks in the rear? You may want to check the install for tightness there maybe something loose or it could be axle wrap. Some people have reported that the spring leaf spacers coming out. I also had a situation where the spare tire was loose on my 96 2500HD everytime I would start out it made a clunk. Just a thought.

It has blocks in the rear, I will also check to make sure they're tight. That would be funny if it was the spare tire swinging, but I'm not that lucky, will check anyways. I will post results when I get it resolved, thanks everyone for the great suggestions, what a great site. :ro)

 

Found the culprit, dry drive shaft splines. Easy fix, thanks for helping out everyone. I double checked the u-bolts and spare tire and everything is tight as well. Drives like new again!!!

 

Wow - glad you found it. These "clunks" can be annoying.

 

My rear end was loose. Had to tighten backlash in rear end gears. EAsy to check driveshaft movemtn w/rear end movement.

 

Great news I will need to check mine for the spline issue, not clunk yet but best to prevent it before it occurs. Has to be some wear on the splines if it aint greased regularly I suppose. Wife told me I had to keep this one until the wheels fall off. Enjoy the ride.

 

I know this thread is all wrapped up but I thought I would add to it incase someone else found a clunk they couldn't resolve.

My first diesel was was an 02 that a cowboy owned before me and spent a lot of time on dirt roads. I could have sworn that a dry drive shaft was the problem and the dealer greased it and we could still hear a bit of a clunk, sometimes from a dead stop and sometimes going over speedbumps. We checked every bolt and finally I think I got the suggestion from another DP member that told me to go to the side of the bed and shake the crap out of it. So I thought what the heck and sure enough I could duplicate the noise. The problem was the rear leaf springs were dry and dirty which would cause them to stick a little bit making the noise. The only thing that you can really do other than replacing them was to spray some cleaner between the springs to loosen things up and then take a power washer to it to try to get some of the junk out of them.

I know this wasn't the problem here but incase someone has tried everything else and see's this thread maybe it will save them some heartache.

 

I've got the same clunk, I will check the spline.

 

Mine's doing the samething ('05 with 40,000 mi). Dealer feels it is in the rearend and want to rip it apart. I am going to grease my driveshaft tonight and see if it helps. I'll let you know.

 

My 01 had a terrible clunk and two dealers said (its the allison transmission and its big gears in there) ignorant.Pulle the center slip yokr apart and greased and it has vot mad a sound in 70,000 miles.

 

I just traded in my 2001 silverado 1500 that had the same clunk. Never did resolve that issue. I also know of two other Silverado 1500 owners that have the same issue. I'll have to let then know about this possible cure. Thanks for posting!!

 

There's a TSB for the clunk. Lot's or reading if you search.
http://dieselplace.com/forum/showthread.php?t=35007&highlight=01-04-17-004B

Greasing works. The grease GM recommends is pricy though.
http://www.gmdieseltech.com/store2/...com/store2/cart.php?target=product&action=view&product_id=16188&category_id=268

 

First time I greased mine I used what I had, cheap grease. The clunk was there, but not as bad. I went out and bought expensive syn. Mobil brand from Advance auto and applied it very heavy inside the drive shaft front spline area and even a thin layer outside the yoke area. ALL CLUNK GONE when stopping and starting.

 

Can some one tell me how hard this is to do, it is driving me nuts, do I need to unbolt the drive shaft from the rear end or is there a grease fitting. Thanks for the help!

 

Use a 11 mm wrench, and unbolt the u-joint from the rearend, and be careful to not have the ujoint caps come off, wrap it in tape. Then slide the yoke out, and grease the heck out of the splines inside the yoke, and then remove the tape and reinstall the shaft in reverse order.

Easy as eating apple pie while drinking sweet tea!

 

Thanks for the help, I will have to do it this weekend.

 

Thanks for the help, I will have to do it this weekend.

Ddonkey, Make sure you mark the location of the drive shaft at the front so you know where to re-install it at. It HAS to slide back in at the very spot it came out due to your drive shaft being balanced.

Use good quality syn. grease. I finally spent the money and used Mobil 1
after using a cheaper grease it was better, but still did it a little. Mobil 1 took care of it.