Help locating a thump on acceleration

Reply Subscribe

Thread Tools

Search this Thread

Jul 21, 2010 | 11:19 PM

stevorino

Thread Starter

Tuned

Joined: May 2003

Posts: 454

Likes: 1

From: College Station TX

Help locating a thump on acceleration

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?

Jul 22, 2010 | 05:42 AM

Brown Falcon

Hotshot

Joined: Jul 2008

Posts: 11,231

Likes: 130

From: Thomasville, GA

U-joints? Balljoints?

Jul 22, 2010 | 07:53 AM

Action4478

Hotshot

Joined: Aug 2006

Posts: 10,764

Likes: 39

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

Jul 22, 2010 | 09:03 AM

Talyn

Hotshot

Joined: Oct 2003

Posts: 17,799

Likes: 104

From: Ashland City, TN

where is husstler with the fender bolts picture.

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

Jul 22, 2010 | 10:08 AM

plgebbia

Posting Guru

Joined: Mar 2008

Posts: 1,537

Likes: 0

From: Dongola, IL

Quote:

Originally Posted by stevorino

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.

Jul 22, 2010 | 10:11 AM

pjwoolw

Postmaster

Joined: Nov 2005

Posts: 3,168

Likes: 10

From: San Ramon Ca.

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

Jul 22, 2010 | 11:21 AM

tjbeggs

Post Fiend

Joined: Apr 2004

Posts: 12,835

Likes: 3

From: Silver Lake Dunes, MI

Quote:

Originally Posted by Action4478

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

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.

This Hennessey Takes the Expedition Tremor's Off-Roading Capability to the Next Level

Verdad Gallardo

Top 10 Fords at 2026 Carlisle Ford Nationals

Joe Kucinski

3 Best / 3 Worst Parts of Modern Ford Ownership

Brett Foote

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

Pouria Savadkouei

Every 2026 Ford Engine Explained

Brett Foote

10 Ugly Ford Trucks That We Still Kinda Love

Joe Kucinski

10 Things Every Truck Owner NEEDS (2026 Edition)

Michael S. Palmer

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Verdad Gallardo

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Joe Kucinski

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Brett Foote

Jul 22, 2010 | 12:22 PM

tjbeggs

Post Fiend

Joined: Apr 2004

Posts: 12,835

Likes: 3

From: Silver Lake Dunes, MI

Quote:

Originally Posted by Action4478

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!

Jul 25, 2010 | 11:15 PM

#10

stevorino

Thread Starter

Tuned

Joined: May 2003

Posts: 454

Likes: 1

From: College Station TX

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