# ZF 3HP transmission

The 3HP is a 3-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.
Gear Ratios :
| GearModel | R | 1 | 2 | 3 | Total Span | Span Center | Avg. Step | Compo- nents |
| 3HP 12 Small Engines | −2.000 | 2.560 | 1.520 | 1.000 | 2.560 | 1.600 | 1.600 | 2 Gearsets 3 Brakes 2 Clutches |
| 3HP 12 Big Engines | −2.000 | 2.286 | 1.429 | 1.000 | 2.286 | 1.512 | 1.512 | 2 Gearsets 3 Brakes 2 Clutches |
| 3HP 22 Big Engines | −2.086 | 2.479 | 1.479 | 1.000 | 2.479 | 1.575 | 1.575 | 2 Gearsets 3 Brakes 2 Clutches |
| 3HP 22 Small Engines | −2.086 | 2.733 | 1.562 | 1.000 | 2.733 | 1.653 | 1.653 | 2 Gearsets 3 Brakes 2 Clutches |
| 3HP 22 Porsche 944 | −2.429 | 2.714 | 1.500 | 1.000 | 2.714 | 1.648 | 1.648 | 2 Gearsets 3 Brakes 2 Clutches |

## 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.
Gear Ratios :
| With Assessment | With Assessment | Planetary Gearset: Teeth Ravigneaux | Planetary Gearset: Teeth Ravigneaux | Count | Total Center | Avg. |
| Model Type | Version First Delivery | S$_1$ R$_1$ | S$_2$ R$_2$ | Brakes Clutches | Ratio Span | Gear Step |
| Gear Ratio | | R ${i_{R}}$ | | 1 ${i_{1}}$ | 2 ${i_{2}}$ | 3 ${i_{3}}$ |
| Step | | $-{\tfrac {i_{R}}{i_{1}}}$ | | ${\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{2}}}$ | ${\tfrac {i_{2}}{i_{3}}}$ |
| Δ Step | | | | | ${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$ | |
| Shaft Speed | | ${\tfrac {i_{1}}{i_{R}}}$ | | ${\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{2}}}$ | ${\tfrac {i_{1}}{i_{3}}}$ |
| Δ Shaft Speed | | $0-{\tfrac {i_{1}}{i_{R}}}$ | | ${\tfrac {i_{1}}{i_{1}}}-0$ | ${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$ |
| 3HP 12 | 160 N⋅m (118 lb⋅ft) 1963 | 25 32 | 32 64 | 3 2 | 2.5600 1.6000 | 1.6000 |
| Gear Ratio | | −2.0000 $-{\tfrac {2}{1}}$ | | 2.5600 ${\tfrac {64}{25}}$ | 1.5200 ${\tfrac {38}{25}}$ | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 0.7825 | | 1.0000 | 1.6842 | 1.5200 |
| Δ Step | | | | | 1.1080 | |
| Speed | | -1.2800 | | 1.0000 | 1.6842 | 2.5600 |
| Δ Speed | | 1.2800 | | 1.0000 | 0.6842 | 0.8758 |
| 3HP 12 | Big Engines 1963 | 28 32 | 32 64 | 3 2 | 2.2857 1.5119 | 1.5119 |
| Gear Ratio | | −2.0000 $-{\tfrac {2}{1}}$ | | 2.2857 ${\tfrac {16}{7}}$ | 1.4286 ${\tfrac {10}{7}}$ | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 0.8750 | | 1.0000 | 1.6000 | 1.4286 |
| Δ Step | | | | | 1.1280 | |
| Speed | | -1.1429 | | 1.0000 | 1.6000 | 2.2857 |
| Δ Speed | | 1.1429 | | 1.0000 | 0.6000 | 0.6842 |
| Ratio | | $-{\tfrac {R_{2}}{S_{2}}}$ | | ${\tfrac {R_{1}R_{2}}{S_{1}S_{2}}}$ | ${\tfrac {R_{2}(S_{1}+R_{1})}{S_{1}(S_{2}+R_{2})}}$ | ${\tfrac {1}{1}}$ |
| Algebra And Actuated Shift Elements |||||||
| Brake A | | | | | ❶ | |
| Brake B | | | | | ❶ | |
| Brake C | | ❶ | | ❶ | | |
| Clutch D | | | | ❶ | ❶ | ❶ |
| Clutch E | | ❶ | | | | ❶ |
| ↑ Layout Input and output are on opposite sides Planetary gearset 2 (the outer Ravigneaux gearset) is on the input (turbine) side Input shafts is, if actuated S$_1$ or S$_2$ Output shaft is R$_2$ (the ring gear of the outer Ravigneaux gearset ↑ Total Ratio Span (Total Ratio Spread · Total Gear Ratio) ${\tfrac {i_{n}}{i_{1}}}$ A wider span enables the downspeeding when driving outside the city limits increase the climbing ability when driving over mountain passes or off-road or when towing a trailer ↑ Ratio Span's Center $(i_{n}i_{1})^{\tfrac {1}{2}}$ The center indicates the speed level of the transmission Together with the final drive ratio it gives the shaft speed level of the vehicle ↑ Average Gear Step $({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$ With decreasing step width the gears connect better to each other shifting comfort increases ↑ Sun 1: sun gear of gearset 1: inner Ravigneaux gearset ↑ Ring 1: ring gear of gearset 1: inner Ravigneaux gearset ↑ Sun 2: sun gear of gearset 2: outer Ravigneaux gearset ↑ Ring 2: ring gear of gearset 2: outer Ravigneaux gearset 1 2 3 4 Standard 50:50 — 50 % Is Above And 50 % Is Below The Average Gear Step — With steadily decreasing gear steps (yellow highlighted line Step) and a particularly large step from 1st to 2nd gear the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger and the upper half of the gear steps (between the large gears; rounded up, here the last 1) is always smaller than the average gear step (cell highlighted yellow two rows above on the far right) lower half: smaller gear steps are a waste of possible ratios (red bold) upper half: larger gear steps are unsatisfactory (red bold) 1 2 3 4 5 Standard R:1 — Reverse And 1st Gear Have The Same Ratio — The ideal reverse gear has the same transmission ratio as 1st gear no impairment when maneuvering especially when towing a trailer a torque converter can only partially compensate for this deficiency Plus 11.11 % minus 10 % compared to 1st gear is good Plus 25 % minus 20 % is acceptable (red) Above this is unsatisfactory (bold) 1 2 3 Standard 1:2 — Gear Step 1st To 2nd Gear As Small As Possible — With continuously decreasing gear steps (yellow marked line Step) the largest gear step is the one from 1st to 2nd gear, which for a good speed connection and a smooth gear shift must be as small as possible A gear ratio of up to 1.6667:1 (5:3) is good Up to 1.7500:1 (7:4) is acceptable (red) Above is unsatisfactory (bold) 1 2 3 From large to small gears (from right to left) ↑ Standard STEP — From Large To Small Gears: Steady And Progressive Increase In Gear Steps — Gear steps should increase: Δ Step (first green highlighted line Δ Step) is always greater than 1 As progressive as possible: Δ Step is always greater than the previous step Not progressively increasing is acceptable (red) Not increasing is unsatisfactory (bold) ↑ Standard SPEED — From Small To Large Gears: Steady Increase In Shaft Speed Difference — Shaft speed differences should increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one 1 difference smaller than the previous one is acceptable (red) 2 consecutive ones are a waste of possible ratios (bold) ↑ Blocks R$_1$ (ring gear of the inner Ravigneaux gearset) and S$_2$ (sun gear of the outer Ravigneaux gearset) ↑ Support link with freewheel · blocks R$_1$ (ring gear of the inner Ravigneaux gearset) and S$_2$ (sun gear of the outer Ravigneaux gearset) in one direction ↑ Blocks C$_1$ and C$_2$ (the common Ravigneaux carrier 1 + 2) ↑ Couples S$_1$ (sun gear of the inner Ravigneaux gearset) with the turbine ↑ Couples S$_2$ (sun gear of the outer Ravigneaux gearset) with the turbine |||||||

## 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 Ratios :
| With Assessment | With Assessment | Planetary Gearset: Teeth Simpson | Planetary Gearset: Teeth Simpson | Count | Total Center | Avg. |
| Model Type | Version First Delivery | S$_1$ R$_1$ | S$_2$ R$_2$ | Brakes Clutches | Ratio Span | Gear Step |
| Gear Ratio | | R ${i_{R}}$ | | 1 ${i_{1}}$ | 2 ${i_{2}}$ | 3 ${i_{3}}$ |
| Step | | $-{\tfrac {i_{R}}{i_{1}}}$ | | ${\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{2}}}$ | ${\tfrac {i_{2}}{i_{3}}}$ |
| Δ Step | | | | | ${\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}$ | |
| Shaft Speed | | ${\tfrac {i_{1}}{i_{R}}}$ | | ${\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{2}}}$ | ${\tfrac {i_{1}}{i_{3}}}$ |
| Δ Shaft Speed | | $0-{\tfrac {i_{1}}{i_{R}}}$ | | ${\tfrac {i_{1}}{i_{1}}}-0$ | ${\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}$ | ${\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}$ |
| 3HP 22 | 320 N⋅m (236 lb⋅ft) 1963 | 35 73 | 35 73 | 3 2 | 2.4795 1.5746 | 1.5746 |
| Gear Ratio | | −2.0857 $-{\tfrac {2}{1}}$ | | 2.4795 ${\tfrac {181}{73}}$ | 1.4795 ${\tfrac {108}{73}}$ | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 0.8412 | | 1.0000 | 1.6759 | 1.4795 |
| Δ Step | | | | | 1.1328 | |
| Speed | | -1.1888 | | 1.0000 | 1.6759 | 2.4795 |
| Δ Speed | | 1.1888 | | 1.0000 | 0.6759 | 0.8035 |
| 3HP 22 | Small Engines 1973 | 35 73 | 41 73 | 3 2 | 2.7331 1.6532 | 1.6532 |
| Gear Ratio | | −2.0857 $-{\tfrac {73}{35}}$ | | 2.7331 ${\tfrac {6983}{2555}}$ | 1.5616 ${\tfrac {114}{73}}$ | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 0.7631 | | 1.0000 | 1.7501 | 1.5616 |
| Δ Step | | | | | 1.1207 | |
| Speed | | -1.3103 | | 1.0000 | 1.7501 | 2.7331 |
| Δ Speed | | 1.3103 | | 1.0000 | 0.7501 | 0.9829 |
| 3HP 22 | Porsche 944 1981 | 28 68 | 32 64 | 3 2 | 2.7143 1.6475 | 1.6475 |
| Gear Ratio | | −2.4286 $-{\tfrac {17}{7}}$ | | 2.7143 ${\tfrac {19}{7}}$ | 1.5000 ${\tfrac {3}{2}}$ | 1.0000 ${\tfrac {1}{1}}$ |
| Step | | 0.8947 | | 1.0000 | 1.8095 | 1.5000 |
| Δ Step | | | | | 1.2063 | |
| Speed | | -1.1176 | | 1.0000 | 1.8095 | 2.7143 |
| Δ Speed | | 1.1176 | | 1.0000 | 0.8095 | 0.9048 |
| Ratio | | $-{\tfrac {R_{1}}{S_{1}}}$ | ${\tfrac {S_{1}(S_{2}+R_{2})+R_{1}S_{2}}{S_{1}R_{2}}}$ | ${\tfrac {S_{1}(S_{2}+R_{2})+R_{1}S_{2}}{S_{1}R_{2}}}$ | ${\tfrac {S_{2}+R_{2}}{R_{2}}}$ | ${\tfrac {1}{1}}$ |
| Algebra And Actuated Shift Elements |||||||
| Brake A | | | | | ❶ | |
| Brake B | | | | | ❶ | ❶ |
| Brake C | | ❶ | | ❶ | | |
| Clutch D | | | | ❶ | ❶ | ❶ |
| Clutch E | | ❶ | | | | ❶ |
| ↑ Layout Input and output are on opposite sides Planetary gearset 1 is on the input (turbine) side Input shafts is, if actuated, S$_1$ or R$_2$ Output shaft is R$_1$ ↑ Total Ratio Span (Total Ratio Spread · Total Gear Ratio) ${\tfrac {i_{n}}{i_{1}}}$ A wider span enables the downspeeding when driving outside the city limits increase the climbing ability when driving over mountain passes or off-road or when towing a trailer ↑ Ratio Span's Center $(i_{n}i_{1})^{\tfrac {1}{2}}$ The center indicates the speed level of the transmission Together with the final drive ratio it gives the shaft speed level of the vehicle ↑ Average Gear Step $({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}$ With decreasing step width the gears connect better to each other shifting comfort increases ↑ Sun 1: sun gear of gearset 1: inner Ravigneaux gearset ↑ Ring 1: ring gear of gearset 1: inner Ravigneaux gearset ↑ Sun 2: sun gear of gearset 2: outer Ravigneaux gearset ↑ Ring 2: ring gear of gearset 2: outer Ravigneaux gearset 1 2 3 4 5 Standard 50:50 — 50 % Is Above And 50 % Is Below The Average Gear Step — With steadily decreasing gear steps (yellow highlighted line Step) and a particularly large step from 1st to 2nd gear the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger and the upper half of the gear steps (between the large gears; rounded up, here the last 1) is always smaller than the average gear step (cell highlighted yellow two rows above on the far right) lower half: smaller gear steps are a waste of possible ratios (red bold) upper half: larger gear steps are unsatisfactory (red bold) 1 2 3 4 5 6 7 Standard R:1 — Reverse And 1st Gear Have The Same Ratio — The ideal reverse gear has the same transmission ratio as 1st gear no impairment when maneuvering especially when towing a trailer a torque converter can only partially compensate for this deficiency Plus 11.11 % minus 10 % compared to 1st gear is good Plus 25 % minus 20 % is acceptable (red) Above this is unsatisfactory (bold) 1 2 3 4 5 6 7 Standard 1:2 — Gear Step 1st To 2nd Gear As Small As Possible — With continuously decreasing gear steps (yellow marked line Step) the largest gear step is the one from 1st to 2nd gear, which for a good speed connection and a smooth gear shift must be as small as possible A gear ratio of up to 1.6667:1 (5:3) is good Up to 1.7500:1 (7:4) is acceptable (red) Above is unsatisfactory (bold) 1 2 3 4 From large to small gears (from right to left) ↑ Standard STEP — From Large To Small Gears: Steady And Progressive Increase In Gear Steps — Gear steps should increase: Δ Step (first green highlighted line Δ Step) is always greater than 1 As progressive as possible: Δ Step is always greater than the previous step Not progressively increasing is acceptable (red) Not increasing is unsatisfactory (bold) ↑ Standard SPEED — From Small To Large Gears: Steady Increase In Shaft Speed Difference — Shaft speed differences should increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed) is always greater than the previous one 1 difference smaller than the previous one is acceptable (red) 2 consecutive ones are a waste of possible ratios (bold) ↑ Blocks S$_1$ ↑ Support link with freewheel · blocks S$_1$ in one direction ↑ Blocks C$_1$ (the planetary gear carrier 1) ↑ Couples S$_1$ with the turbine ↑ Couples R$_2$ with the turbine |||||||