Hi folks, I am looking for some help locating a thump, thud or similar knock in my truck as I accelerate from a start. It almost feels like something large in the back is engaging just after the truck starts moving(nothing is rolling around in the bed). It's the kind of thing that can drive you crazy just wondering what it is. I crawled underneath the truck today and took a look but I couldn't find anything suspicious. The transmission mount looks good and the suspension seems tight. The only small issues are that the leaf spring bushings could probably use replacing and the teflon spacers in the leaf springs are shot, but I don't think just that would make such a bump. Could it be the differential? Anyone else experienced this?

 

U-joints? Balljoints?

 

Slip joint on the rear drive shaft need greasing?..

 

where is husstler with the fender bolts picture.


Check the bolts on the front fenders up by the hood latches.

 

Put the truck in nuetral on a flat surface. Then crawl under the truck and without rolling the truck at all try to turn the driveshaft back and forth to see if there is excessive play. It could be caused by u-joints, worn slip joint, worn differential, and maybe even a bad carrier bearing.

 

Also check the rear spring bushings and shackles. Springs too come to think of it. That was my mystery thunk.

 

Maybe its a pintle hitch behind the seat in the cab........

Slip joint is where I would look too if all the u-joints are good.

 

Good memory ,,,






Taking up comedy in your spare time also Eh...

 

I'm the boss today and tomorrow. Gotta do something to keep the sanity!

 

Thanks for the suggestions fellas. I am finally able to get to the computer again..... I had the driveshaft completely rebuilt and balanced about 2 years ago, so I'm thinking that's not it, and it doesn't seem to have any play in it. I also have noticed that it is a thump, thump. Like something is engaging twice or bumping twice. I have thought about unloading every last thing from my tool box and cab just to make sure it's not something in there, but I can't find anything that would make such a significant bump.

I just read back through the thread and realized I had forgotten about the slip joint issue. I have done that once before and it took care of something similar. I should just put a zerk fitting on it. Thanks for the reminder Action4478. My money is on this fix. I might have time to do that tomorrow.

Also, I do need to check my fender bolts. I put a pallet of wood flooring on the truck today and they creaked pretty bad when the truck frame twisted. It could have something to do with rear-ending that Lexus last summer. It tweaked the panels and hood up front but my grill guard won that battle. F350 - 1; Lexus -0