I've become worried about the "clunks" coming from the rear end (it is most obvious when going from first to reverse). It is a 10-bolt, PA code in a 68. At first it sounded like bad u-joints but I changed them and all is well there. I've also ruled out motor mounts (the sound is from the rear anyway). I jacked up the rear and rotated the wheels --it seemed like there was a lot of slop before the gears engaged. Does this sound like a set of gears with a bit of wear or something more serious? I know--hard to tell but I thought I'd ask anyway.

Thanks in advance

Hold the yoke and see if you can move it up and down or side to side. Any movement other than rotation is bad and means that either the nut backed off or the pinion bearings are going bad.

Thanks Big Gear Head. I appreciate your help.