The 4-speed automatic ZF 4HP22 was produced at a German company from 1980 to 2004 and was installed on many popular rear-wheel drive and all-wheel drive cars with powerful V6, V8 engines. This transmission is known as the transmission of the Discovery and Range Rover of the first generations.
4HP family: 4HP14, 4HP16, 4HP18, 4HP20, 4HP22, 4HP24.
Specifications
| Production years | 1980 – 2004 |
| Type | automatic transmission |
| Number of gears | 4 |
| Type of drive | all wheel / rear |
| Engine volume, l | up to 4.0 |
| Torque output, Nm | up to 380 |
| Recommended oil | Dexron III |
| Oil capacity, liter | 8.0 / 9.5 |
| Partial replacement, liter | 4.0 |
| Maintenance | every 60 000 km |
| Gearbox lifespan, km | ~400 000 |
| Weight, kg | 84 |
In 1980, the ZF concern introduced a new 4-speed automatic transmission with hydraulic control, which was intended for rear-wheel drive models with a longitudinal engine. In 1986, the gearbox was slightly modernized due to the appearance of an electronic control unit, and a 4HP22EH version appeared for all-wheel drive Land Rover Discovery and Range Rover. Separately, we note the 4HP22HL modification for the Porsche 911 with a rear-mounted unit.
By design, this is a classic hydromechanical automatic transmission, built according to a typical design from a Raviño dual planetary gearbox with a conventional gearbox and 7 clutch packs.
Gear ratios ZF 4HP22
Using the example of a Land Rover Discovery 1999 with a 4.0 liter engine:
| Main | 4.285 |
| 1st | 2.479 |
| 2nd | 1.479 |
| 3rd | 1.000 |
| 4th | 0.728 |
| Reverse | 2.086 |
Using
The transmission was installed on:
- BMW 3-Series E30 in 1982 – 1994;
- BMW 5-Series E28 in 1981 – 1988; 5-Series E34 in 1988 – 1993;
- BMW 6-Series E24 in 1982 – 1989;
- BMW 7-Series E23 in 1982 – 1986; 7-Series E32 in 1986 – 1994;
- Chevrolet Opala 1 in 1988 – 1992;
- Jaguar XJ 4 (XJ40) in 1986 – 1994; XJ 5 (X300) in 1994 – 1997;
- Land Rover Discovery 1 (LJ) in 1992 – 1998; Discovery 2 (L318) in 1998 – 2004;
- Land Rover Range Rover 1 (LH) in 1987 – 1996; Range Rover 2 (P38A) in 1994 – 2002;
- Lincoln Continental 7 in 1983 – 1985;
- Lotus Excel 1 (Type 89) in 1986 – 1992;
- Maserati Biturbo 1 (AM331) in 1988 – 1994;
- Maserati Quattroporte 4 (AM337) in 1994 – 1998;
- Peugeot 505 I (551A) in 1986 – 1992;
- Peugeot 604 I (561A) in 1981 – 1985;
- Porsche 911 III (964) in 1989 – 1994; 911 IV (993) in 1994 – 1998;
- Volvo 740 I (744) in 1984 – 1992;
- Volvo 760 I (764) in 1982 – 1990;
- Volvo 940 I (944) in 1990 – 1995.
Disadvantages of the ZF 4HP22 gearbox
- The service life of this very reliable gearbox depends almost entirely on driving style. For an active owner, the torque converter locking clutch can wear out up to 200 thousand km, then vibrations appear that break the oil pump bushing and leaks begin.
- Also, wear products of the torque converter clutch clog the solenoids and channels of the valve body, which causes delays when shifting gears, various shocks and jerks.
- Many complaints are related to the automatic transmission going into emergency mode due to electrical failures, and the culprit is both the gear selector and the engine ECU or ABS sensors.
