My fiance's 02 Supercab XLT 4wd automatic has a strange clunk when leaving from the stop. This truck is 99% street driven and according to carfax the previous owner had it under a lease. I don't see any signs of offroading as the paint is super clean/no dents anywhere on the body or frame so I doubt he was hotrodding it on the trails.

The clunk happens when you leave a stop under in low to moderate acceleration. I can't feel it under hard acceleration.

The clunk happens once or twice leaving from a stop, you can't hear it at all. You can just feel it. There is also no humming from the rear or front. The clunk feels like it's coming from the rear. I've been under there a couple time rackin on the driveshaft back and forth as well as trying to rotate it (tires still on the ground) and there is zero movement. I also haven't noticed any unusual amount of play in the rear axle with the rear end jacked up off the ground.

Any tips for trying to diagnose the problem? My first thought is u joints but I've never had to mess those before. My last 2 rangers (lowered 2wd) never had a problem like this so I've never had to dick with it. I'm also not a 4wd guy so I wouldn't know where to start with checking the front end for possible known problems on these trucks. I'm 99& certain this clunk is in the drivetrain and not in the suspension.

again, it's a 2002 4.0 4wd automatic supercab. 1 piece drive shaft and 8.8 rear end, 4.10 gear with factory limited slip (all factory)

 

I would check the U-joints. If it were a 2 piece drive shaft I would say grease the slip yoke.

 

aside from pulling the u joints out is there a way to check them? I live in a damn apartment complex and we aren't allowed to work on our vehicles here. I can get away with poking around on the truck but it would be a big no-no to start removing major parts like that. I am hoping that I can just poke around to find the problem and then we can take it to her mom's house and tear it apart.