A method of testing a braking device in a drivetrain of a vehicle which includes at least one tractive element coupled to a traction motor. The method includes: (a) applying the braking device to a tractive element of the vehicle; (b) using an electronic controller, causing the traction motor to apply a predetermined force to the tractive element; and (c) using the controller, monitoring the tractive element for movement while the force is being applied. A dynamic braking or “retarder” function may also be tested. A system for carrying out the method is provided.