Rear end clunk on deceleration (intermittent)

[Oxford White]

I've owned the truck for about a year. 2005 V8 AWD. It's got 101K miles and ever since owning it every once in a while, about 15% of the time, there is a thud or clunk coming from the rear when decelerating. This has occurred with or without braking so I have ruled out the brakes as the culprit.

The noise has not worsened or improved since I've owned it and didn't change when I replaced the rear end oil (with M1 75/140 & TransX). My first thought was that there was play in the gears or failing U-joint. I've searched through 11 pages here and with all of the problems people have with the rears none seem to fit the problem I'm having. Other than the clunk the rear is not making other odd noises.

None of the wheels have play and the left rear had a bearing replaced already so it seems suspension-wise all is OK. Anyone else have this problem, or had it fixed, or could recommend a possible suggestion to the cause of this noise?

BTW, the truck's for sale for cheap, and other than this noise it's in excellent condition.

 

[buzman78]

Your problem sounds similar to mine -Downshift Problem!! Like you hit something- and I've wondered if my problem was really the rear causing the noise and I'm ready with the M1 and Motorcraft Friction Modifier. See what you think.

 

[Oxford White]

Changing the oil didn't help me. My first thought is it's not transmission related in my case because it's sporadic and seems to occur at different downshift points, meaning not just from 2-1, but 4-3 or 3-2. The downshift just seems to bring out the play. (But then again, why wouldn't I get the clunk accelerating as well if that were the case...I'm lost.)

 

[RickM]

Two possible solutions come to mind.....

One being the Valve Body and or solenoid pack in the Trans. There are a few very informative threads here on the forum discussing the upgrade.

The second is a "computer (E/EEPROM)" code upgrade. Some have reported that dealerships typically charge around $90 for the upload service.

 

[IZwack]

Isnt this the classic sympton of a loose pinion bearing? Disconnect the rear driveshaft from the rear differential and check for play.

 

[Oxford White]

Thanks everyone. I'll look into those possibilities.

 

[gruber1223]

Let me know what you find out. I'm having similar problems. Mine never done it until I replaced the tires, now I'm getting a clunk when I'm decelerating. I just can't figure this one out!

 

[Oxford White]

Mine is so intermittent and it's been the same for a year now so I'm not doing anything until it ever starts getting worse.

 

[Oxford White]

Mine is so intermittent and it's been the same for a year now so I'm not doing anything until it ever starts getting worse.

 

[Oxford White]

Mine is so intermittent and it's been the same for a year now so I'm not doing anything until it ever starts getting worse.

 

[gruber1223]

I pulled the 4x4 fuse (#12 in the fuse box) to see if it may be a 4x4 problem. Sure enough, my clunking has stopped....so far! I just pulled it this evening and drove it for 20-30 miles and haven't had any clunking yet. Sounds like the same problem that you described! I'll keep you posted if I can narrow down the actual problem.

 

[Oxford White]

Good luck...hope you solve it.