BillyBobJoe

Hey everyone. I know this is a repeating topic, and a lot of time it ends up being the u-joints, but I still seem to be at square one. I've got a 2003 F150 4x2. It's got just under 80,000 miles on it with plenty of regular maintenance (or at least I'd like to think so). When shifting from Park to Drive or Reverse, or Drive to Reverse, Reverse to Drive, etc, I hear what sounds like a clunk and almost a lurching. Now I know the lurch is somewhat normal but i feel the clunk shouldn't be. I crawled under the car in Neutral and shook/rotated/moved the driveshaft (one-piece) and didn't see much play on the tranny side or axle side. I used a camera to watch the rear u-joint as I shifted and didn't see much play in the u-joint, but I did notice a good half a turn or so of the driveshaft whenever the transmission shifted.

Any ideas? I'm worried that my gear and pinion may be fudged up. Thanks for the help guys.

fatscrew

sounds like a u-joint. i wouldnt think there should be any play in them what so ever and they will also cause a chirping and vibration when they begin to fail. along with the clunk when changing gears

billmck04

If the U-joints are tight, It might be time to pull off the diff cover and check the pinion shaft and spider gears for wear - and check for pinion gear movement. Sounds like excessive wear in the differential.

BillyBobJoe

I'm considering replacing the u-joints as a precautionary method at this point regardless, but I'm not sold on that being the problem. I've gone under the truck again and i can't get any play out of the u-joints. If the shaft moves, so does the pinion.

zap

It could be the torque converter actually. Sounds like it is seizing up at low rpm.