Clunking

[JoJoJim]

2001 2500 HD 8.1 Allison 4whl dr. During the last week once in a while after sitting at a stop light just as starting to accelerate I get a clunk clunk clunk from under neath it somewhere. 5 or 6 clunks and goes away. Has only done this about once per day. I check the ujoints and appear to be good. I did have the drive shaft serviced (lube job kit) a couple of weeks ago. This is in 2wd when doing it. I would think ujoint problem would do it each time during a start up. I don't hear or feel anything else that is unusual. I need help and appreciate it very much.

Thanks,

[ColoradoSkiCountry]

What kind of lube did they use on the drive shaft. Also do you have a 4X4? If so, the transfer case may need the GM blue fluid in it. Very common issue with the 99-03/04 1500s with 4X4, ended up needing the slip yoke replaced with an updated nickle plated slip yoke which solved most of the clunking problems. Also using the right GM transfer case fluid is critical as well, many after market stuff does not do the job well.

[Big black truck]

I bet the carrier bearing is shredded. Mine did the same and the rubber was torn. You can only get them at a gm dealer....I think I pd $128. Get under the car and get someone to put it in drive and neutral, you will see the slop.