BMW 318/325/M3/525/535/M5 1989-1993 Repair Information



See Figure 1

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Fig. Fig. 1: Components of the ZF 4HP-22 transmission

Most of the automatic transmissions used by BMW are manufactured by ZF. They are 4 speed overdrive units with torque converter lockup and electronic controls. They can be identified by a single oil sump.

All of the M50 engine and some of the M42 engine equipped vehicles are supplied with transmissions manufactured by Hydra-Matic. The Turbo-Hydra-Matic units also feature 4 speeds with a lockup torque converter and electronic controls. They can be identified by a dual oil sump.

A variety of transmissions are used, usage being determined by the chassis and engine combination. By chassis and engine, this is the application:

E30 3 SeriesM20 engine-4HP 22M42 engine-4HP 22S14 engine-not available
E36 3 SeriesM42 engine-THM-R1M50 engine-THM-R1
E34 5 SeriesM20 engine-4HP 22M30 engine-4HP 22M50 engine-THM-R1S38 engine-not available