240D Shifter Problems--almost got me flattened on Highway
 

I am having Chronic "locking" and "catching" and "missed gear" shifter problems with my 1983 240D and its really driving me crazy. I dont think the problem is the Transmission since they are supposed to be really tough, and I have replaced all the shifter bushings and tightened the Linkages and aligned them and realigned them carefully.
The other day I lost 3 rd gear and 4 th Gear in the mountains for awhile ahead of a Big Truck until I really whacked the shifter and unlocked it
I am wondering whether the problem is the shifter assembly itself? Do these ever go bad?
I have corrected everything else--the shifter calibration, the bushings and linkages.

240D Shifter Problems--almost got me flattened on Highway