Automatic Transmission problems of the 2002 BMW X5

Transmission problems on a 2002 BMW X5 3. 0 automatic with 69000 miles. The vehicle slips in reverse, at times it does not work at all. I've conducted all scheduled maintenance since purchased from original owner. I took car to a shop who services BMW's and they checked the transmission fluid, which was ok. Later after doing research on problems with BMW transmission I was amazed on how many complaints there are with the BMW transmission. If I would of known of the problem I would of not bought this vehicle or any BMW. I was told from mechanics that work on this vehicle it will cost me around $5000. 00 to replace the transmission and sooner or later it will fail because their transmissions are sealed and do not require fluids or major servicing. After doing additional research online for any recall information BMW has not submitted one whatsoever. I am pretty sure BMW is aware of the problem and knowing a recall will cost them alot of money, they refuse to admit an ongoing problem with their transmissions. I purchased this vehicle at a reasonable price but with me being the only income in my household (military) I simply cannot afford the repair. I do not expect any resolution from BMW, however, I want to file this complaint to create awareness for future consumers of BMW automobiles. This will be my first and only BMW. Thank you for your attention.

Car has been well maintained with regular service. 80,000 miles. No indication of any problem on start up. Experienced sudden total loss of transmission function. The car rolls when in park. A grinding sound is noted in cabin.