2003 Duramax Diesel clunk

[Joe H]

I get a drive line clunk at operating tempatures when starting and stopping. Noticed mostly at take-off. Does anyone out there have a fix? I would appreciate any advice on the matter.

[Jim Brzozowski]

Check the u-joints on the driveshaft for wear.

[Timberwolf]

Could be u-joints, or something else. Where is the clunk coming from? ie. front, back, left, right, etc.

[DmaxMaverick]

It is very likely your output spline is in need of some grease. When you stop, spring wind-up occurs in the leafs. When you take off, the spline sticks, then releases in a "clunk", as the springs swing to the other extreme. GM's "fix" for this is to grease the spline with a HP lithium grease.


I'm moving this topic to the Drivetrain Forum.

[ 07-29-2005, 06:34 PM: Message edited by: DmaxMaverick ]

[jbplock]

Dittos to DmaxMaverick

[REDTRUCK05]

[quote]Originally posted by jbplock:
[b] Dittos to DmaxMaverick

[REDTRUCK05]

Originally posted by Joe H:
I get a drive line clunk at operating tempatures when starting and stopping. Noticed mostly at take-off. Does anyone out there have a fix? I would appreciate any advice on the matter. My 2005 is doing the same thing. I Have a posting on the main site under "Low speed bang"

[Nine 0 Nine]

my dad had the same issue. I checked the diff lube after checking all the u-joints, they looked OK. The diff lube looked like a$$ though. Black and very light. does anyone know if the nickel output yoke is going to be a replace even if out of warranty item? The truck has 28k on it but is beyond the 3 years. Has anyone tried to lube up with HD lithium and see if it stops? If this is an out of warranty item, I may just do it for him to save a few hundred bucks from the stealer.

[REDTRUCK05]

Originally posted by Joe H:
I get a drive line clunk at operating tempatures when starting and stopping. Noticed mostly at take-off. Does anyone out there have a fix? I would appreciate any advice on the matter. My dealer said that it might be the addaptive shift patterns of the tranny. Do you pull? Does this happen soon after you pulling the trailer?

[BJohn]

Joe (and any other "clunkers" out there)...I also had the "clunk" on take-off with my 2001 2500 D/A CC. My truck has the two-piece driveshaft. I decided to heed the advice I gleaned from reading this forum (thanks everyone!)and crawled under to start to remove the shaft and lube it myself. I noticed from some shiny marks that the carrier bearing support for the driveshafts was slipping back and forth about an inch or so. I tightened the two retaining bolts and took a drive. No more clunk! 7,000 miles since without any problems. I've since gone ahead and lubed the splines anyway, just for kicks, with Mobil1 grease.
Every so often I also take the weight off the rear springs, flush them with water then lube them with Silicone spray. That seems to smooth out the ride when unloaded. Good Luck! John

[Dalmation6]

Greetings All,
This happened to me also. I bought the GM Lithium Lube from Eric Merchant at gmdieseltech.com. It isn't cheap for a pint can. I crammed as much as I could inside the slip yoke and I haven't had a problem since. It's been about 3 weeks and my wife even noticed the difference. I also replaced the intermediate steering shaft, man what a difference. The Lube is necessary for that drive shaft (two piece) I'm way out of warranty, 03 D/A CC 74,000 miles. Didn't want to spend dinero with the dealer. I fixed all the problems my self for $130.00. Took about 45-60 minutes to do both jobs.
ALSO Check the drive shaft boot to make sure that it isn't torn. I had to get a new one (dealer only) for 25.00