I bet you've got a 90% chance that you need to replace the bushings in the linkage. Will set you back about five bucks. While you're under there, check the front end of the transmission where the linkages connect to the transmission. There is an allen bolt recessed in the holes that can come loose when exposed to undue stress like from when the bushings are worn out or missing.

BTDT with my manual transmission.

Len
'83 240D 342,000 miles original owner