My 1985 BMW ,standard transmission suddenly developed shifting problem. It will not shift into 1st, 3rd or 5th gear. It will shift into reverse,2nd and 4th gear. The car is not driven on any frequent schedule, infrequently. I can’t remember the last time the transmission oil was changed.There has not been any mechanical distress,grinding of gears,etc. you just cant engage those gears. They all are moving the shifter from neutral to a up position. Is it possible that sludge could be blocking the movement of the synchronize r?
Sounds like a linkage problem, those are pretty common. Do you have a shop familiar with old BMWs? It might be some worn or broken plastic pieces. They should be able to tell pretty quickly.
Do you have anything deceased in the shift linkage? It sounds like an obstruction keeping the lever from moving forward. I’d start by just looking inside the car under the shifter boot. Maybe something fell into the console and is preventing the shifter from moving. Second, check under the car for that obstruction while a buddy shifts the lever forward. Next step is to start to disassemble the shifter, you’ll need to anyway if the transmission needs to come out, That would be the 4th step. Good luck.