You can only find transfer case in four-wheel drive and all-wheel drive car as a special gear box. The drive power was sent from engine to the front and rear axles by transfer case. There is lubricant fluid inside the transfer case keeping the gear cool and turning smoothly. There are some symptoms showing you need to replace your transfer case: if the transfer case fluid is dirty, or if your BMW car is unable to change gears, you need to buy a new transfer case as soon as possible. We understand you cherish your car as much as your every family member. For us, we cherish every customer. We reduce the price to attract more customers, and we offer all BMW genuine OEM transfer case with a surprising low price.