I have a '97 F150 4x4 4.6 V8 auto. Whenever i take off from a dead stop and slowly give it gas the truck goes but then does a real quick jerk in the rear end. And if i stomp on the gas it does it right away. But after it does it once from take off it never seems to do it again. I have a feeling that it might be my ring and pinion gears. I looked at the drive shaft and didn't feel any looseness in the u joints. But i did notice that when i push the truck back and forth the drive shaft doesnt turn right away with the wheels. Has anyone had this problem. Please help!!!

 

Two things:

The front bolt on the left rear leaf spring comes loose -- allowing the spring (and accompanying axle) to shift for and aft.

Secondly, make sure your driveshaft slip joint is lubricated.

 

Thanks, i'll be sure to check that in the morning. Also, there seems to be some play when i shake the truck side to side. It seems like it might have to do with my lugnuts, but i made sure they were tight. Maybe that has to do with the same problem, huh?
Thanks again.

 

have your rear axle checked by someone qualified [other than the deaeler] it's probably like mine wore out at 39000 miles

 

Yea, im also thinking about getting it checked out soon. It has 120,000 miles on it, and its prolly about time. Plus, im gonna be upgrading the power and that will prolly be the first thing to go out.