fx4_soldier

Didnt run me anything cuz my truck is covered under a 3 year warranty!!! but the dealership who did it, messed it up so i gotta take it in wednesday, but yes the slip yoke fromn the transmission to the driveshaft is what was causing the thump on my truck, i was worried it was the rear end til i took it in, hopefully it something as small as this for you!! good luck man

thump

After some more internet research I'm pretty sure that's it. It appears that once the grease dries out that the yoke starts to bind a bit. Seems to be a common problem. All I should need to do is drop the driveshaft and regrease the splines.

Thanks, fx4_soldier... and welcome to the forum.

tdg0830

My 05 FX4 does it and 2 of my buddies 06 Lariat's do it.

EddyCarr

I had the same problem on my 2006 with 43k. Thought it might off been my diff or a joint, it was way too soon for my tranny to go out! But everything seemed fine under the microscope. Worked out it was my torque converter, which i replaced and now no more thump!