Driveline Vibration

Shaners · July 7, 2004

My truck has developed a vibration on launch after I come to a stop. It's a chatter in the seat of your pants for about a second and it is hard to duplicate.

The problem occurs "only" after I have driven a distance (8+ miles) without stopping and the torque converter has been locked up. The tranny temp has to be over 140* or it doesn't happen. For example when starting out at the stop sign at the end of an Expressway exit ramp.

I had the driveshaft TSB done on the truck, and now I have a one-piece drive shaft so that shouldn't be a problem. The tranny is full, and the fluid is red. The truck has 16K miles on it...

My dealer said the possible cause could be my +1 size 265/75/16 tires... (I'm not convinced this is the case).

Any ideas? The truck is in the shop right now for it's final warranty service.

snoman · July 8, 2004

This is pretty easy to guess the cause. It is in the drive shaft. It might be a joint going bad but I really suspect that it is improper aliignment of drive shaft ujoint angles (this is why it had a 2 piece shaft to begin with which should have been properly balanced and not replaced) Ujoints are not constant velocity as the flex and with more than 3 degrees for flex a "shudder" can sometimes be felt as the velocity accross the joint varies while turning. The solution (assuming you check joints and they are good) it to try to proper align joint angle to eliminate this problem or go back to a 2 piece shaft. The alignment problem will most likely be a rear axle end.

1BADHD · July 8, 2004

My brother has that in his truck. Its the rear diff. He has been told it wont hurt anything. Its just annoying. They told him somthing about the clutch packs hanging up.

snoman · July 8, 2004

My brother has that in his truck. Its the rear diff. He has been told it wont hurt anything. Its just annoying. They told him somthing about the clutch packs hanging up.

That will not cause problem in straight line driving though. GM put a two piece drive shaft on that truck to begin with to limit u-joint angles. Two piece drive shafts are more sensitive to balancing problems and I have never seen a drive shaft from the factory that was balanced properly to begin with. I had to rebalance the shaft on my 89 burb when it was new at my expensive to cure a "rumble" at certain cruising speeds.

8100HD · July 8, 2004

Shaners, I also believe that there was a TSB for the slip-yoke, may want to make sure they replaced that when they did the driveshaft.

1BADHD · July 8, 2004

My brother has that in his truck. Its the rear diff. He has been told it wont hurt anything. Its just annoying. They told him somthing about the clutch packs hanging up.

That will not cause problem in straight line driving though. GM put a two piece drive shaft on that truck to begin with to limit u-joint angles. Two piece drive shafts are more sensitive to balancing problems and I have never seen a drive shaft from the factory that was balanced properly to begin with. I had to rebalance the shaft on my 89 burb when it was new at my expensive to cure a "rumble" at certain cruising speeds.

No matter if he is turning or not. If he drives then comes to a stop and reaccelerates, it "shimmies" for a few seconds.

The slip yoke was a bandaid fix. GM no longer covers that TSB. It would eventually come back. Now the 2 piece drive shaft is a legit thing to look at.

snoman · July 8, 2004

My brother has that in his truck. Its the rear diff. He has been told it wont hurt anything. Its just annoying. They told him somthing about the clutch packs hanging up.

That will not cause problem in straight line driving though. GM put a two piece drive shaft on that truck to begin with to limit u-joint angles. Two piece drive shafts are more sensitive to balancing problems and I have never seen a drive shaft from the factory that was balanced properly to begin with. I had to rebalance the shaft on my 89 burb when it was new at my expensive to cure a "rumble" at certain cruising speeds.

No matter if he is turning or not. If he drives then comes to a stop and reaccelerates, it "shimmies" for a few seconds.

The slip yoke was a bandaid fix. GM no longer covers that TSB. It would eventually come back. Now the 2 piece drive shaft is a legit thing to look at.

My nickle is on drive angle of rear yoke joint. You could try to install about 2 degress of caster shim between rear axle and spring pads to tilt nose of diff up a bit (or down if it is too high for shaft angle) .

Shaners · July 8, 2004

Thanks for the replies...

GM went to a 1-piece drive shaft on all the crewcab shortbeds for '02 because of a driveline shudder that was caused by the carrier bearing for the 2-piece shafts. I had that shudder and it was immediatly cured by the giant aluminum 1-piece shaft. I believe the angle was corrected when the shaft was installed.

Here's the deal though... I can drive all day long in 90* temps in town (with a hot tranny) and never feel the shudder when I take off... It ONLY occurs after I have traveled a distance of 6-8+ miles in "3" or "OD" with the torque converter locked up, and then after I come to a stop and go to take off it shudders. It will not do it unless the tranny is at least 140* after I have driven the above distance.

1BADHD · July 8, 2004

Hmmm....that does sound tranny or converter related. Check your tranny fluid? Still nice and red? Smell burnt?

snoman · July 8, 2004

GM went to a 1-piece drive shaft on all the crewcab shortbeds for '02 because of a driveline shudder that was caused by the carrier bearing for the 2-piece shafts. I had that shudder and it was immediatly cured by the giant aluminum 1-piece shaft. I believe the angle was corrected when the shaft was installed.

I have had 2 piece driveshaft run smooth as silk if they were balanced correctly. If they are not they can vibrate around carrier bearing area. I suspect that that was GM's cheap fix for a poor balancing job from factory to begin with.

Shaners · July 8, 2004

I have had 2 piece driveshaft run smooth as silk if they were balanced correctly. If they are not they can vibrate around carrier bearing area. I suspect that that was GM's cheap fix for a poor balancing job from factory to begin with.

That was billed out at about $1100 for the new driveshaft if I remember correctly. It's 1.5-2 times the diameter of the old one and is nice shiny aluminum.

I had the driveshaft replaced around 10-12K ago, and the new vibration started happening about 1k ago.

I would think I could make the vibe happen all the time, but it is only after a short non-stop trip with warm tranny...

snoman · July 9, 2004

I have had 2 piece driveshaft run smooth as silk if they were balanced correctly. If they are not they can vibrate around carrier bearing area. I suspect that that was GM's cheap fix for a poor balancing job from factory to begin with.

That was billed out at about $1100 for the new driveshaft if I remember correctly. It's 1.5-2 times the diameter of the old one and is nice shiny aluminum.

I had the driveshaft replaced around 10-12K ago, and the new vibration started happening about 1k ago.

I would think I could make the vibe happen all the time, but it is only after a short non-stop trip with warm tranny...

It would have to be a lot larger for torsional rigidity on a long span. Have you checked the Ujoints on the shaft for tightness?

Shaners · July 9, 2004

It would have to be a lot larger for torsional rigidity on a long span. Have you checked the Ujoints on the shaft for tightness?

I have not checked them, but I will because I got the truck back from the dealer tonight... I wondered if a U-joint could be the problem. But I still don't understand why I could put 50 miles on the truck in stop and go traffic and not have the problem, but if I run 10 miles non-stop down the interstate, it'll vibrate after the first stop when I go to start out.

snoman · July 9, 2004

It would have to be a lot larger for torsional rigidity on a long span. Have you checked the Ujoints on the shaft for tightness?

I have not checked them, but I will because I got the truck back from the dealer tonight... I wondered if a U-joint could be the problem. But I still don't understand why I could put 50 miles on the truck in stop and go traffic and not have the problem, but if I run 10 miles non-stop down the interstate, it'll vibrate after the first stop when I go to start out.

You must remember that alumimun expands and "grows" a lot more with heat than steel does and if it is a balance or joint problem it could be agravated by this expansion on the freeway from the added heat and stress.