Classic 140 acceleration hesitation
 

98 S500

Always when cold, I'll get a very slight jerk/hesitation when first starting out - like the first few feet. It won't do it until the next morning when cold. It's almost un-noticable.

I replaced the flex disks, and the shaft bearings which looked shot anyway. But symptoms still there. Here's my nightmare - Could this be the 1st gear clutche(s)? That'd mean a new tranny. It does this either in S or W (1st or 2cd).

Actually it feels like it's a slip coming from the differential! I flushed/changed the diff oil - didn't see any big metal in the fluid. It's like the diff is having to "warm up" - it only does this little hesitation once. Also could this be somewhere in the antiskid? Wheel speed sensors maybe? This car does not have the MB posi-traction (ASR), nor ESB. But does have a brake-assisted acceleration non-skid.

No codes. Any ideas?