The 1st generation Toyota Tacoma PreRunner has a RWD drivetrain that uses a rear differential to transfer power from the transmission to the rear wheels. As opposed to a 4WD vehicle which employs the use of a front differential, transfer case, and rear differential to transfer power to all four wheels, a PreRunner with RWD only has a rear differential to service. With regular driving, Toyota suggests inspecting the rear differential fluid every 15,000 miles. My Haynes Manual recommends to replace the differential fluid every 30,000 miles. On my parents’ Tacoma, they don’t do any towing. Their truck sits at a bit over 30k miles so I went ahead and did the first rear differential fluid change on this truck.