2500 HD Driveline Vibration

Paul's 2500HD · January 13, 2021

I have a 2006 Chevy 2500HD Extended cab pickup. It has a 6 liter gas engine. Automatic transmission, and 4 wheel drive. The truck has 170,000 miles on it. And is stock, as it was bought. And it has never plowed snow.

Some time ago it developed a driveline vibration at 70, MPH. A trans shop replaced the back half of the transfer case. The original drive shaft (a one piece driveshaft) was balanced. with no improvement.

Recent u joint replacement. Then a new driveshaft was made. The pinion yoke was replaced. The carrier was replaced with a new TrueTrac. All the rear end bearings were replaced. And the pinion was checked for runout.

The truck also had the tires balanced, and later replaced with 4 new Firestone tires. Oddly enough in testing, WITH THE REAR AXLES REMOVED and the driveline brought up to 70, the vibration remains.

Eliminating the tires or brakes as a balance concern. Or is the ring and pinion - loading drag on the transfer case, or transmission causing the vibration?

But with the rear driveshaft removed, the vibration is gone. Leading back to a driveline vibration? Or once again, is the ring and pinion - loading drag on the transfer case, or transmission causing the vibration?

Has anyone else experienced this concern. The truck has about 200 pounds of tools in the front of the box.

The truck currently has two codes. One is a knock sensor, likely from the vibration. And one for a random misfire. And I understand the crank sensor needs to be reset.

I really don't know what other information I could offer? The truck is currently in a reputable repair shop, with older experienced mechanics.

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