1996 GMC Sierra Z71 transmission clunk - Snowmobile Forum: Your #1 Snowmobile Forum

Cdndairyman · 06-29-2009, 06:56 PM

Hey guys my truck is making a bad clunking sound when shifting from reverse to drive. It doesn't do it from part straight to drive only when I back up then stop and put it in drive. It will clunk as I let off the brake and it starts to roll forward. I was wondering if anyone had any idea what this is and what I could check. I am not a mechanic so anything to invasive would be probably too much for me!

**RJ Gleason** · 06-29-2009, 07:07 PM

Check the drive shaft u-joints.

**smallengineguy** · 06-30-2009, 07:28 AM

X2 on the U-joints. Chock the wheels and put it in neutral. Then you can twist the driveshaft back and forth by hand and check the U-joint at the back attaching to the rearend.

Cdndairyman · 06-30-2009, 07:57 AM

I wondered if it was getting bad u joints but I didn't think that noise was from that. I will check it out and go from there! Thanks for your help!

**RJ Gleason** · 06-30-2009, 09:54 AM

GMC/Chevy = notorious for losing U-joints.
Make sure that you get Moog greaseable replacement ones. They have a much longer life.
Also check that none of the balance weights are pushed put by rust or are missing. I hd to have a shaft rebalanced because of this and it solved the problem too.