kckndrgn

I am getting a "clank" noise, sound like metal hitting metal. This will usually only happen at slow speeds, like driving in a parking lot, when I take my foot off the accelerator.

I can duplicate it by pressing the accelerator to start moving, the pull my foot off. I instantly hear "clank".

I have had this truck at 2 different mechanics who have test drove it for other reasons, but neither has said anything about the noise, this would leave me to believe that I should not be concerned about it. Should I be?

This is an '87 F150 w/ 5.8L engine. I'm not sure which transmission is in it, but it is an automatic.

Thanks for any help
Ryan

1996 Redneck F150

the ring and pinion in the rear end might have slack in it and need replaced.... or it could be something as simple as a u-joint thats gone bad in the drive shaft

kckndrgn

What do I need to look for in each situation? I may not fix it myself, but I like to know for future reference.

1996 Redneck F150

jack the back end of your truck up... block the front wheels with a piece of wood or something (just so it wont roll forward).... put the truck in neutral.... get underneath the truck and wiggle the rear driveshaft up and down and side to side (on each u-joint).... if you have slack in ANY u-joint what so ever, then you need to replace the u-joint that has slack.... now the ring and pinion im not to sure about.... if im not mistaken, then you need to follow the above steps but leave the truck in gear.... get underneath the truck, and turn the driveshaft back and forth.... the driveshaft shouldnt turn more than a half a turn???? im not really for sure.... maybe someone else on here knows a little more about that than i do.... ive never had a ring and pinion go bad on me (knock on wood)

kckndrgn

ok, got underneath the truck last weekend with the father-in-law and neither of us could find anything wrong. Everything was nice and tight.

I did check the fluid in the differential and it was a little low, so I topped it off.

I still have the noise. Don't know if this is "normal" or not, but I would prefer it not to make the noise.

dkitt10

first thing that comes to mind is u-joint...did you park on level ground and put it in neutral to take tension off drive shaft

kckndrgn

Ok, just checked something at lunch. When I put the truck into reverse, I get "clank". Then I put it into drive, "Clank" again. If I go back to reverse it's "CLANK!"

This all with the foot on the brake, not moving. Looks like I'll be replacing U-joints this weekend. OH JOY!

kckndrgn

Ok, got underneath again. All U-joints appear to be good. I can twist the drive shaft and make the "clank" noise, sounds like its coming from the differential. The drive shaft was twisting about 1/2" to 3/4".

So, is there something wrong is the differential?

Thanks for any and all help

1996 Redneck F150

sounds to me like you need a new ring and pinion gear

kckndrgn

ok, got a new/used axle in today. I noticed the same play where the driveshaft ties into the diff. Should there be any? I was under the assumption that it should be fairly tight without much movement.

Thanks