Assuming you would like an answer for a domestic car such as a Ford F-150, it would cost between $1,200 and $1,500 to replace the transfer case. This includes the cost of parts and labor; however, the price may vary depending on your location. If you have a four-wheel drive truck, then your transfer case will be more expensive to replace than if you have a two-wheel drive truck.
The transfer case is located in the middle of your vehicle, beneath the transmission. It is responsible for sending power from the engine to the front and rear axles. The front axle receives power through a driveshaft while the rear axle is powered by gears inside the transfer case itself. Over time, these gears can wear down or break completely, which will require replacing the entire unit.
If you are experiencing problems with your four-wheel drive system, it is generally best to take it to a mechanic rather than attempting to fix it yourself. Transfer cases are complex systems and requires special tools and knowledge to repair properly. In addition, many newer vehicles have electronic components that control how power is distributed to each axle; these also need to be diagnosed by a professional before any repairs are attempted.