I have a 2006 F 150 SCAB 2WD with about 6700 miles on it. Lately, I've been feeling a sort of "thunk" on acceleration from a stop. And it only happens when accelerating from a stop.

I had it on a lift yesterday, and all the U joints appear tight, springs and shock bushings are all good, and there in no backlash in the pinion. The only thing that I could see that would move is the driveshaft center bearing, and the only motion there is in the rubber, I can shake the front driveshaft back and forth a little, but only as far as the the rubber deflects.

I'm the original owner on this truck and it has never been wrecked or driven off road. I sometimes tow a two axle car trailer, and the truck has never been overloaded.
Anyone have any thoughts on this? I hate to take it to the dealer because I'm tired of being ripped off by them.

Thanks in advance, John

 

The slip yoke needs to be greased.

https://www.f150online.com/forums/ot...line-lube.html

 

Yep .... my '77 will do that when it wants grease in the slip joint.