If there is a leak in the rear of a vehicle's transmission, where is it likely coming from?

A leak in the rear of a vehicle's transmission is most likely to originate from the output shaft seal. This seal is designed to prevent transmission fluid from leaking out where the output shaft exits the transmission housing. As the vehicle operates, fluid pressure can cause wear on the seal, particularly in high-stress conditions or over extended use, leading to potential leaks.

The output shaft is responsible for transferring power from the transmission to the drive shaft that ultimately powers the wheels. Therefore, a leak in this area directly impacts the function of the transmission and can lead to significant performance issues if not addressed.

While the other options could potentially result in leaks, they are not typically associated with leaks specifically at the rear of the transmission. The transmission pan is located on the bottom of the transmission and is more often a source of leaks due to rust or damage, the dipstick tube primarily affects access for fluid levels rather than causing rear leaks, and the torque converter, although it can have issues related to leakage, does not directly contribute to rear transmission leaks like the output shaft seal does.