The wife's 93 AWD Aerostar is making a "thunk" in the left front when you stop & go from fwd to rev or vice versa. I think it's also causing a slight vibration. I suspected hub or halfshaft. I jacked up the front, the only thing I detect is play from left to right, none up & down. It doesn't appear to be the tie rod. Both wheel seem to go fwd & rev about the same, no grinding or excessive looseness. The half-shaft appears to be turning okay, no cracks in the boot or anything. Upper control arm bushings look fine.

Anyone have a guess?

Thanks,
Biederboat