I get a slight drive train clunk when backing out of my driveway when I put it in drive and accelerate (even lightly). It’s almost as if the splines of the driveshaft are sliding the other way causing the noise. Ford has solved the problem before by lubing something, but I not sure what, and now it out of warranty. I need to lube again. Heard of this?

 

My best guess would be a U-joint. That sounds like the usual symptoms. But once they start making noise it is generally time for a replacement. I guess a lube job may give some temporary relief.

 

04F250:

Just went thru that w/ my '90. Discovered what the prob was when the rear part of the rear drive shaft (it's a 2 piece rear drive shaft) fell out @ the u-joint/yoke where it connects to the front part of it (toward the transmission) while driving down the hiway. Kinda scary. Luckily, the disconnected end didn't dig in to the asphalt (was doing 60 mph).