hello,

I have a weird symptom developing. It goes a little like this...

1.) When accelerating (light or heavy) from a stop the truck begins to move as expected, no problem from inital take off...

2.) just after the truck begins to move (say around 2 MPH) there is a drivetrain "jolt" much like one would expect to have with worn U-Joints; however, the U-joints are fine. There is no audible clunk or any other noise but a jolt can be felt just after take-off.

Has anyone experienced this? If so what was the diagnosis and/or fix?

Thanks in advance.

 

Carrier bearing? Any shudder/vibration at any other time?

 

when you take-off from a stop the pinion rises as the force of the driveshaft twists, maybe a loose or broken spring/axle u-bolt? maybe a leaf spring shackle binding or rusted?

 

just a thought might be a broken motor mount or trans mount!!

 

Had an '87 3/4 ton (4 spd), which I bought new, that did something like this after owning it for a year or two. When coming to a complete stop, like at a light, the rear diff apparently would twist slightly and the springs would "wrap" a bit...then unload when you'd drive away from the stop...making a noticeable clunk. I think that there was a TSB out on this at the time. The dealer sprayed white grease between the spring plies and the clunk would disappear until the grease wore off. I kept a can in the truck and would lube it up whenever the clunk came back.