Cant get reverse gear when car is hot on my bmw x5

try changeing the oil in the box. try changeing the oil in the box.

you could try changing the transmission fluid. It might help. If not then change the TCC solenoid (means draining and refilling the trans fluid again). That may or may not work. If not, remove the valve body inside the trans pan and have it rebuilt. (means having the trans oil drained and refilled. Personally, instead of trying the job three times, I would just have the valve body rebuilt which takes care of all the problems and extends the life of the transmission another 100-150k miles (1500$ parts and labor) and save time and trouble, and about 3-400 $ in experimenting money. you could try changing the transmission fluid. It might help. If not then change the TCC solenoid (means draining and refilling the trans fluid again). That may or may not work. If not, remove the valve body inside the trans pan and have it rebuilt. (means having the trans oil drained and refilled. Personally, instead of trying the job three times, I would just have the valve body rebuilt which takes care of all the problems and extends the life of the transmission another 100-150k miles (1500$ parts and labor) and save time and trouble, and about 3-400 $ in experimenting money.