Towing vibration

[CoastyAV8R]

I notice when I hook our trailer up to the truck or load the bed up with dirt/bark/whatever, I feel a vibration at lower rpms that seems like the rear u-joints. I think what is happening is when the truck gets loaded, the angle of the driveshaft changes when the rear end squats (about 3" from stock) from the weight as I don't feel it when the truck is unloaded or lightly loaded with a few dirt bikes.



My question is it possible for u-joint to work fine in one position that they run in 90% of the time and but vibrate when the angle the have to operate is changed? Anybody seen this before?



The truck has 80,000 miles on it and is a long bed 6 speed.



Thanks,



Patrick

 

[BarryG]

On my 01 auto after I had the trans rebuilt I had to shim the carrier bearing down 1/2 an inch. I had a noticable vibration at take off and between 50-60ish when pulling my trailer and trying to accelerate.



I called the guy who built my trans told him what was going on and that it hadn't done it before the rebuild and he said oh yeah sometimes we have to shim the bearing start at 1/2 inch and go in 1/4 inch increments after that until resolved. 1/2 did it for me.



You are right about the changing angle the added weight on the rear end coupled with spring wrap is too much for the u joints angle wise.

 

[MAshley]

Short answer Yes



Long answer, it may also just be the extra weight, and slight change in angle. My rear driveshaft was replaced at 26,000 miles, the rear carrier baring went bad. I did tow a heavy trailer 14,000lbs worth during this time.



David

06 4x4 Dully, LB Quad cab