ZF 3HP transmission

The 3HP is a three-speed Automatic transmission family with a hydrodynamic Torque converter with hydraulic control for passenger cars from ZF Friedrichshafen AG. In selector level position "P", the output is locked mechanically. The Ravigneaux planetary gearset types were first introduced in 1963 and produced through the mid seventies. The Simpson planetary gearset types were launched in 1973 and produced through 1990. Both were used in different versions in a large number of cars.

3HP 12 · 3HP 22
Overview
Manufacturer	ZF Friedrichshafen
Production	1963–1975 · 1973–1990
Model years	1963–1975 · 1973–1990
Body and chassis
Class	3-Speed Automatic Transmission for Longitudinal and Transverse Engines
Chronology
Successor	ZF 4HP transmission Family

1963: 3HP 12 · Ravigneaux Planetary Gearset Types

Introduction

The 3HP 12 was produced through the mid-seventies and has been used in a variety of cars. There are versions for longitudinal and transverse engines.

Specifications

Gear Teeth and Ratios		Planetary Gearset Teeth Ravigneaux		Count	Total	Avg.
Model	Version First Delivery	${S_{1}}$ ${R_{1}}$	${S_{2}}$ ${R_{2}}$	Brakes Clutches	Ratio Span	Gear Step
Gear $n$		R		1	2	3
Step $i_{n-1}/i_{n}$		–R : 1			1 : 2	2 : 3
3HP 12 Small Engines	1963	25 32	32 64	3 2	2.5600	1.6000
Ratio $i_{n}$		−2.0000 $-{\tfrac {2}{1}}$		2.5600 ${\tfrac {64}{25}}$	1.5200 ${\tfrac {38}{25}}$	1.0000 ${\tfrac {1}{1}}$
Step		0.7813			1.6842	1.5200
3HP 12 Big Engines	160 N⋅m (118 lb⋅ft) 1963	28 32	32 64	3 2	2.2857	1.5119
Ratio $i_{n}$		−2.0000 $-{\tfrac {2}{1}}$		2.2857 ${\tfrac {16}{7}}$	1.4286 ${\tfrac {10}{7}}$	1.0000 ${\tfrac {1}{1}}$
Step		0.8750			1.6000	1.4286
Ratio		$-{\tfrac {R_{2}}{S_{2}}}$		${\tfrac {R_{1}R_{2}}{S_{1}S_{2}}}$	${\tfrac {R_{2}(S_{1}+R_{1})}{S_{1}(S_{2}+R_{2})}}$	${\tfrac {1}{1}}$

1973: 3HP 22 · Simpson Planetary Gearset Types

Introduction

The all new 3HP 22 was introduced in 1973 and was produced through 1990 and has been used in a variety of cars from Alfa Romeo, BMW, Citroën, Peugeot, and Fiat.

Specifications

Weight	45 kg (99 lb) with converter
Control	mechanical · hydraulic

Gear Teeth and Ratios		PlanetaryGearset Teeth Simpson		Count	Total	Avg.
Model Type	Version First Delivery	$S_{1}$ $R_{1}$	$S_{2}$ $R_{2}$	Brakes Clutches	Ratio Span	Gear Step
Gear $n$		R		1	2	3
Step $i_{n-1}/i_{n}$		–R : 1			1 : 2	2 : 3
3HP 22 Big Engines	320 N⋅m (236 lb⋅ft) 1973	35 73	35 73	3 2	2.4795	1.5746
Ratio $i_{n}$		−2.0857 $-{\tfrac {73}{35}}$		2.4795 ${\tfrac {181}{73}}$	1.4795 ${\tfrac {108}{73}}$	1.0000 ${\tfrac {1}{1}}$
Step		0.8412			1.6759	1.4795
3HP 22 Small Engines	1973	35 73	41 73	3 2	2.7331	1.6532
Ratio $i_{n}$		−2.0857 $-{\tfrac {73}{35}}$		2.7331 ${\tfrac {6,983}{2,555}}$	1.5616 ${\tfrac {114}{73}}$	1.0000 ${\tfrac {1}{1}}$
Step		0.7631			1.7501	1.5616
3HP 22 Porsche 944	1981	28 68	32 64	3 2	2.7143	1.6475
Ratio $i_{n}$		−2.4286 $-{\tfrac {17}{7}}$		2.7143 ${\tfrac {19}{7}}$	1.5000 ${\tfrac {3}{2}}$	1.0000 ${\tfrac {1}{1}}$
Step		0.8947			1.8095	1.5000
Ratio		$-{\tfrac {R_{1}}{S_{1}}}$	${\tfrac {S_{1}(S_{2}+R_{2})+R_{1}S_{2}}{S_{1}R_{2}}}$		${\tfrac {S_{2}+R_{2}}{R_{2}}}$	${\tfrac {1}{1}}$

See also

• list of ZF transmissions