Transmission Not Go Into Gear problems of the 2002 BMW M3

Multiple incidents since the day after we purchased the car: ?driving in 4th gear (anywhere from 10 to 40 mins of driving) will suddenly feel as if clutch is engaged so I cannot accelerate, yellow transmission warning light comes on, then I have to coast to a complete stop and shut the engine off. It can take several attempts to restart the car to re-engage back into 1st gear. Noticed if I wait long enough, once the transmission warning light also turns off then I can restart back in first gear. All this while driving in auto mode. ?same issue as above but has happened in the lower gears while accelerating or when cruising at higher gears, for example, 6th gear and manually shifting into 5th, warning light will come on, car will not be in gear, will have to coast to a stop and attempt to restart with 1st gear again. ?same issue as above, but has happened while parked at a red light, indicator shows 1st gear, but when I try to go, the warning light comes on and I?m not in gear, requires a stop/restart of engine again ? sometimes multiple tries. This happens on both even, declined and inclined road surfaces. ?this is extremely dangerous as we have been left dead in the road attempting to restart the car while there's on-coming traffic around us!.

Trouble with smg transmission. Car will not stay in gear and bucks hard trying to engage.