The BMW 4HP22 is a four-speed automatic transmission developed by ZF and fitted to a broad range of BMW models throughout the 1980s and into the early 1990s. As one of ZF's most enduring automatic designs, the 4HP22 paired smooth, torque-converter-based shifting with mechanical durability, making it a natural match for BMW's inline-six and V8 engines of the era. Its name follows ZF's convention: 4 forward gears, HP for hydraulic planetary, and 22 denoting the torque class.
What This Gearbox Is and How It Works
The 4HP22 uses a hydrodynamic torque converter feeding a set of planetary gear sets, with shift points governed by a hydraulic valve body. Later BMW applications adopted electronic-hydraulic control (often designated 4HP22EH), which added a control unit to manage shift quality and adapt to driving style. This electronic variant introduced selectable shift programs, a hallmark of BMW's move toward smarter automatics that would fully mature in later ZF units like the 5HP30.
Gear Count and Behavior
As the name implies, the 4HP22 provides four forward speeds plus reverse. In BMW guise it was tuned for relaxed highway cruising and confident part-throttle response, with a lock-up torque converter clutch on many versions to reduce slip and improve efficiency. Compared with the modern multi-ratio boxes that followed, its four ratios feel widely spaced, but for the engines it served the 4HP22 delivered a smooth, unfussy driving character that suited BMW's grand-touring intentions.
Which BMWs Used It
The 4HP22 appeared across several BMW chassis families during its long service life, commonly behind six-cylinder and V8 engines. You'll encounter it in period E28 and E34 5 Series automatics, E24 6 Series coupes, E23 and E32 7 Series sedans, and various E30 3 Series automatics. Because usage varied by year, engine, and market, the most reliable way to confirm what shipped in a specific car is to run the chassis number through our VIN decoder and cross-check the drivetrain history in BMW DNA. As BMW's lineup grew and torque demands rose, the 4HP22 gave way to more advanced units such as the 6HP26.
Reliability and Servicing
The 4HP22 earned a reputation for toughness when properly maintained. Longevity hinges on fluid condition and cooling.
- Fluid service: Use the correct ATF specification and change it at sensible intervals despite any "lifetime" claims.
- Cooling: Keep the transmission cooler and lines clean; heat is the primary enemy of any automatic.
- Symptoms to watch: Delayed or harsh shifts, slipping, or lock-up shudder often trace to worn friction elements or degraded fluid.
- Electronics (EH versions): Inspect the control unit, wiring, and speed sensors before condemning the mechanical hardware.
Well cared for, a BMW 4HP22 can cover high mileage reliably, which is why it remains a respected chapter in BMW's automatic transmission lineage that continued through units like the 6HP19.