Thunking noise
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Joined: Apr 2004
Posts: 18
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From: Fl
Thunking noise
Hello all, I have only posted a few times and I am learning as I go here. I have a 98 f150 4.6 with about 105K on the clock. Whenever I go over spped bumps, there is a loud thunking coming from the back...possibility of needing shocks/struts?? Also, when i am backing up while turning right, it makes a thunking noise too. Could that be tie rods or the sway bar? I have done searches, and the sway bar/tie rod issue is about the best I got out of that. Any help would be greatly appreciated
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Joined: Apr 2003
Posts: 473
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From: mn
My 97 Expy had a similar clunk while backing up and turning the wheel. It did this a couple times then one day at work while backing into a parking spot one of the inner tie rods fell apart and left me with the front wheels turned in opposite directions. Very common problem and Ford sent out a bulletin on checking the tie rod ends frequently.
As far as the back goes there are many things that could cause the noise:
1) Grab the shocks while still attached to the truck and see if they seem loose like if you have bad shock bushings. Rancho shocks with the red polyurethane bushings often cause a clunk because the bushing is hard and fits loosely in the shock.
2) Check and see if you have the rubber pads between the leaves in the spring pack. I don't know if you're supposed to have them but maybe you'll notice one side has them and the other side doesn't. The large rubber o-rings used for hanging exhaust pipes will fit nicely over the end of a leave. Get a couple of them and put one onto the back end of the 2nd or 3rd leave down from the main leave and see if that helps quiet it down. You will have to jack the back of the truck up by the frame and maybe use a pry bar to open it up just enough to slide the o-ring on.
3) Rear sway bar bushings if bad will cause a loud clunk. Get a pry bar between the end of the bar and the end link and see if it's loose or has a lot of movement.
4) Is the spare tire tight under the back of the truck?
5) Bumper, hitch, u-bolts, spring eye bolts tight?
Good luck.
As far as the back goes there are many things that could cause the noise:
1) Grab the shocks while still attached to the truck and see if they seem loose like if you have bad shock bushings. Rancho shocks with the red polyurethane bushings often cause a clunk because the bushing is hard and fits loosely in the shock.
2) Check and see if you have the rubber pads between the leaves in the spring pack. I don't know if you're supposed to have them but maybe you'll notice one side has them and the other side doesn't. The large rubber o-rings used for hanging exhaust pipes will fit nicely over the end of a leave. Get a couple of them and put one onto the back end of the 2nd or 3rd leave down from the main leave and see if that helps quiet it down. You will have to jack the back of the truck up by the frame and maybe use a pry bar to open it up just enough to slide the o-ring on.
3) Rear sway bar bushings if bad will cause a loud clunk. Get a pry bar between the end of the bar and the end link and see if it's loose or has a lot of movement.
4) Is the spare tire tight under the back of the truck?
5) Bumper, hitch, u-bolts, spring eye bolts tight?
Good luck.