Hey guys,

I just picked up a '97 F150 4x4...It clunks when i accelerate from a stop if I put any extra foot down. I can "grandpa" it and it usually won't clunk. It seems to be coming from the drivers side, front...kinda feels like something is shifting towards the rear. I took a look for anything obvious in that area and found nothing. I also jacked up the tire and checked for bad ball joints and tie rod ends. Everything seems ok...any ideas?

 

Maybe look at your motor/trans mounts... A quick visual won't immediately show anything wrong unless the rubber is just straight up missing. I usually have a friend help me check the motor mounts. You'll need a jack to check the trans mount.

 

I had a '97 that started doing that. It was the slip-yoke in the drive shaft. It can wear to the point where there is play in it. When you're on the brake the torsional load can cause it to twist slightly and bind. When you step on the gas, that can "pop" back into alignment, causing the thunk. Might be your case also.

 

Thanks for the replies! I will update as soon as I check these...is there a way to check the slip yoke without tearing it apart?

 

You may be able to give it a yank side to side, up and down and see if it seems to move. If it's minor wear you might not be able to tell that way.