ZF 5HP transmission

5HP is ZF Friedrichshafen AG's trademark name for its 5-speed automatic transmission models (5-speed transmission with Hydraulic converter and Planetary gearsets) for longitudinal engine applications, designed and built by ZF's subsidiary in Saarbrücken.

The 5HP 18 and 19 are a transmission family with purely serial power flow: components were simply added to enable more gears. This makes these transmissions larger, heavier, and more expensive. With 10 main components, progress was unsatisfactory: an obvious transitional solution. It is therefore the last conventionally designed transmission from ZF. All subsequent transmissions from ZF including the 8-speed transmission 8HP require fewer main components.

Gearset Concept: Cost-Effectiveness^[a]

With Assessment	Output: Gear Ratios	Innovation Elasticity[b] Δ Output : Δ Input	Input: Main Components
			Total	Gearsets	Brakes	Clutches
5HP 18/19 Ref. Object	${\displaystyle n_{O1}}$ ${\displaystyle n_{O2}}$	Topic[b]	${\displaystyle n_{I}=n_{G}+}$ ${\displaystyle n_{B}+n_{C}}$	${\displaystyle n_{G1}}$ ${\displaystyle n_{G2}}$	${\displaystyle n_{B1}}$ ${\displaystyle n_{B2}}$	${\displaystyle n_{C1}}$ ${\displaystyle n_{C2}}$
Δ Number	${\displaystyle n_{O1}-n_{O2}}$		${\displaystyle n_{I1}-n_{I2}}$	${\displaystyle n_{G1}-n_{G2}}$	${\displaystyle n_{B1}-n_{B2}}$	${\displaystyle n_{C1}-n_{C2}}$
Relative Δ	Δ Output ${\displaystyle {\tfrac {n_{O1}-n_{O2}}{n_{O2}}}}$	${\displaystyle {\tfrac {n_{O1}-n_{O2}}{n_{O2}}}:{\tfrac {n_{I1}-n_{I2}}{n_{I2}}}}$ ${\displaystyle ={\tfrac {n_{O1}-n_{O2}}{n_{O2}}}}$·${\displaystyle {\tfrac {n_{I2}}{n_{I1}-n_{I2}}}}$	Δ Input ${\displaystyle {\tfrac {n_{I1}-n_{I2}}{n_{I2}}}}$	${\displaystyle {\tfrac {n_{G1}-n_{G2}}{n_{G2}}}}$	${\displaystyle {\tfrac {n_{B1}-n_{B2}}{n_{B2}}}}$	${\displaystyle {\tfrac {n_{C1}-n_{C2}}{n_{C2}}}}$
5HP 18/19 4HP 14/16/18[c]	5[d] 4[d]	Progress[b]	10 7	3[e] 2[e]	3 2	4 3
Δ Number	1		3	1	1	1
Relative Δ	0.250 ${\displaystyle {\tfrac {1}{4}}}$	0.583[b] ${\displaystyle {\tfrac {1}{4}}:{\tfrac {3}{7}}={\tfrac {1}{4}}}$·${\displaystyle {\tfrac {7}{3}}={\tfrac {7}{12}}}$	0.429 ${\displaystyle {\tfrac {3}{7}}}$	0.500 ${\displaystyle {\tfrac {1}{2}}}$	0.500 ${\displaystyle {\tfrac {1}{2}}}$	0.333 ${\displaystyle {\tfrac {1}{3}}}$
5HP 18/19 4HP 20/22/24[c]	5[d] 4[d]	Progress[b]	10 10	3[e] 3	3 4	4 3
Δ Number	1		0	0	-1	1
Relative Δ	0.250 ${\displaystyle {\tfrac {1}{4}}}$	∞[b] ${\displaystyle {\tfrac {1}{4}}:{\tfrac {0}{10}}={\tfrac {1}{4}}}$·${\displaystyle {\tfrac {10}{0}}={\tfrac {10}{0}}}$	0.000 ${\displaystyle {\tfrac {0}{10}}}$	0.000 ${\displaystyle {\tfrac {0}{3}}}$	−0.250 ${\displaystyle {\tfrac {-1}{4}}}$	0.333 ${\displaystyle {\tfrac {1}{3}}}$
5HP 18/19 3-Speed[f]	5[d] 3[d]	Market Position[b]	10 7	3[e] 2[e]	3 3	4 2
Δ Number	2		3	1	0	2
Relative Δ	0.667 ${\displaystyle {\tfrac {2}{3}}}$	1.556[b] ${\displaystyle {\tfrac {2}{3}}:{\tfrac {3}{7}}={\tfrac {2}{3}}}$·${\displaystyle {\tfrac {7}{3}}={\tfrac {14}{9}}}$	0.429 ${\displaystyle {\tfrac {3}{7}}}$	0.500 ${\displaystyle {\tfrac {1}{2}}}$	0.000 ${\displaystyle {\tfrac {0}{3}}}$	1.000 ${\displaystyle {\tfrac {2}{2}}}$
^ Progress increases cost-effectiveness and is reflected in the ratio of forward gears to main components. It depends on the power flow: parallel: using the two degrees of freedom of planetary gearsets to increase the number of gears with unchanged number of components serial: in-line combined planetary gearsets without using the two degrees of freedom to increase the number of gears a corresponding increase in the number of components is unavoidable ^ a b c d e f g h Innovation Elasticity Classifies Progress And Market Position Automobile manufacturers drive forward technical developments primarily in order to remain competitive or to achieve or defend technological leadership. This technical progress has therefore always been subject to economic constraints Only innovations whose relative additional benefit is greater than the relative additional resource input, i.e. whose economic elasticity is greater than 1, are considered for realization The required innovation elasticity of an automobile manufacturer depends on its expected return on investment. The basic assumption that the relative additional benefit must be at least twice as high as the relative additional resource input helps with orientation negative, if the output increases and the input decreases, is perfect 2 or above is good 1 or above is acceptable (red) below this is unsatisfactory (bold) ^ a b Direct Predecessor To reflect the progress of the specific model change ^ a b c d e f plus 1 reverse gear ^ a b c d e of which 2 gearsets are combined as a compound Ravigneaux gearset ^ Reference Standard (Benchmark) 3-speed transmissions with torque converters have established the modern market for automatic transmissions and thus made it possible in the first place, as this design proved to be a particularly successful compromise between cost and performance It became the archetype and dominated the world market for around 3 decades, setting the standard for automatic transmissions. It was only when fuel consumption became the focus of interest that this design reached its limits, which is why it has now completely disappeared from the market What has remained is the orientation that it offers as a reference standard (point of reference, benchmark) for this market for determining progressiveness and thus the market position of all other, later designs All transmission variants consist of 7 main components Typical examples are Turbo-Hydramatic from GM Cruise-O-Matic from Ford TorqueFlite from Chrysler Detroit Gear from BorgWarner for Studebaker BW-35 from BorgWarner and as T35 from Aisin 3N 71 from Nissan/Jatco 3 HP from ZF Friedrichshafen W3A 040 and W3B 050 from Mercedes-Benz

The main objective in replacing the predecessor model was to improve vehicle fuel economy with extra speeds and a wider gear span to allow the engine speed level to be lowered (downspeeding).

Gear Ratio Analysis

In-Depth Analysis With Assessment[a]		Planetary Gearset: Teeth[b]			Count	Nomi- nal[c] Effec- tive[d]	Cen- ter[e]
		Ravigneaux		Simple			Avg.[f]
Model Type	Version First Delivery	S1[g] R1[h]	S2[i] R2[j]	S3[k] R3[l]	Brakes Clutches	Ratio Span	Gear Step[m]
Gear Ratio	R ${\displaystyle {i_{R}}}$		1 ${\displaystyle {i_{1}}}$	2 ${\displaystyle {i_{2}}}$	3 ${\displaystyle {i_{3}}}$	4 ${\displaystyle {i_{4}}}$	5 ${\displaystyle {i_{5}}}$
Step[m]	${\displaystyle -{\frac {i_{R}}{i_{1}}}}$[n]		${\displaystyle {\frac {i_{1}}{i_{1}}}}$	${\displaystyle {\frac {i_{1}}{i_{2}}}}$[o]	${\displaystyle {\frac {i_{2}}{i_{3}}}}$	${\displaystyle {\frac {i_{3}}{i_{4}}}}$	${\displaystyle {\frac {i_{4}}{i_{5}}}}$
Δ Step[p][q]				${\displaystyle {\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}}$	${\displaystyle {\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}}$	${\displaystyle {\tfrac {i_{3}}{i_{4}}}:{\tfrac {i_{4}}{i_{5}}}}$
Shaft Speed	${\displaystyle {\frac {i_{1}}{i_{R}}}}$		${\displaystyle {\frac {i_{1}}{i_{1}}}}$	${\displaystyle {\frac {i_{1}}{i_{2}}}}$	${\displaystyle {\frac {i_{1}}{i_{3}}}}$	${\displaystyle {\frac {i_{1}}{i_{4}}}}$	${\displaystyle {\frac {i_{1}}{i_{5}}}}$
Δ Shaft Speed[r]	${\displaystyle 0-{\tfrac {i_{1}}{i_{R}}}}$		${\displaystyle {\tfrac {i_{1}}{i_{1}}}-0}$	${\displaystyle {\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{5}}}-{\tfrac {i_{1}}{i_{4}}}}$
Specific Torque[s]	${\displaystyle {\tfrac {T_{2;R}}{T_{1;R}}}}$[t]		${\displaystyle {\tfrac {T_{2;1}}{T_{1;1}}}}$[t]	${\displaystyle {\tfrac {T_{2;2}}{T_{1;2}}}}$[t]	${\displaystyle {\tfrac {T_{2;3}}{T_{1;3}}}}$[t]	${\displaystyle {\tfrac {T_{2;4}}{T_{1;4}}}}$[t]	${\displaystyle {\tfrac {T_{2;5}}{T_{1;5}}}}$[t]
Efficiency ${\displaystyle \eta _{n}}$[s]	${\displaystyle {\tfrac {T_{2;R}}{T_{1;R}}}:{i_{R}}}$		${\displaystyle {\tfrac {T_{2;1}}{T_{1;1}}}:{i_{1}}}$	${\displaystyle {\tfrac {T_{2;2}}{T_{1;2}}}:{i_{2}}}$	${\displaystyle {\tfrac {T_{2;3}}{T_{1;3}}}:{i_{3}}}$	${\displaystyle {\tfrac {T_{2;4}}{T_{1;4}}}:{i_{4}}}$	${\displaystyle {\tfrac {T_{2;5}}{T_{1;5}}}:{i_{5}}}$
5HP 18	310 N⋅m (229 lb⋅ft) 1990	38 34[u]	34 98	32 76	3 4	4.9363 4.9363 [d][n]	1.6495
							1.4906 [m]
Gear Ratio	−4.0960[n][d] ${\displaystyle -{\tfrac {1,323}{323}}}$		3.6648 ${\displaystyle {\tfrac {1,323}{361}}}$	1.9990[o] ${\displaystyle {\tfrac {7,938}{3,971}}}$	1.4067 [m][q][r] ${\displaystyle {\tfrac {294}{209}}}$	1.0000 ${\displaystyle {\tfrac {1}{1}}}$	0.7424 ${\displaystyle {\tfrac {49}{66}}}$
Step	1.1176[n]		1.0000	1.8333[o]	1.4211[m]	1.4067	1.3469
Δ Step[p]				1.2901	1.0102[q]	1.0444
Speed	-0.8947		1.0000	1.8333	2.6053	3.6648	4.9363
Δ Speed	0.8947		1.0000	0.8333	0.7719[r]	1.0596	1.2715
Specific Torque[s]	–3.9903 –3.9378		3.5344 3.4700	1.9581 1.9377	1.3861 1.3758	1.0000	0.7385 0.7366
Efficiency ${\displaystyle \eta _{n}}$[s]	0.9742 0.9614		0.9644 0.9468	0.9795 0.9693	0.9854 0.9780	1.0000	0.9948 0.9921
5HP 19	325 N⋅m (240 lb⋅ft) 1997	38 34[u]	34 98	32 76	3 4	4.9363 4.9363 [d][n]	1.6495
							1.4906 [m]
Gear Ratio	−4.0960[n][d]		3.6648	1.9990[o]	1.4067 [m][q][r]	1.0000	0.7424
Actuated Shift Elements
Brake A[v]				❶	❶		❶
Brake B[w]	❶		❶
Brake C[x]	❶		❶	❶
Clutch D[y]			❶	❶	❶	❶
Clutch E[z]	❶
Clutch F[aa]						❶	❶
Clutch G[ab]					❶	❶	❶
Geometric Ratios
Ratio R & 1 Ordinary[ac] Elementary Noted[ad]	${\displaystyle i_{R}=-{\frac {R_{2}(S_{3}+R_{3})}{S_{2}R_{3}}}}$			${\displaystyle i_{1}={\frac {R_{1}R_{2}(S_{3}+R_{3})}{S_{1}S_{2}R_{3}}}}$
	${\displaystyle i_{R}=-{\tfrac {R_{2}}{S_{2}}}\left(1+{\tfrac {S_{3}}{R_{3}}}\right)}$			${\displaystyle i_{1}={\tfrac {R_{1}R_{2}}{S_{1}S_{2}}}\left(1+{\tfrac {S_{3}}{R_{3}}}\right)}$
Ratio 2 & 3 Ordinary[ac] Elementary Noted[ad]	${\displaystyle i_{2}={\frac {R_{2}(S_{1}+R_{1})(S_{3}+R_{3})}{S_{1}R_{3}(S_{2}+R_{2})}}}$				${\displaystyle i_{3}={\frac {R_{2}(S_{1}+R_{1})}{S_{1}(S_{2}+R_{2})}}}$
	${\displaystyle i_{2}={\tfrac {\left(1+{\tfrac {R_{1}}{S_{1}}}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\right)}{1+{\tfrac {S_{2}}{R_{2}}}}}}$				${\displaystyle i_{3}={\tfrac {1+{\tfrac {R_{1}}{S_{1}}}}{1+{\tfrac {S_{2}}{R_{2}}}}}}$
Ratio 4 & 5 Ordinary[ac] Elementary Noted[ad]	${\displaystyle i_{4}={\frac {1}{1}}}$			${\displaystyle i_{5}={\frac {R_{2}}{S_{2}+R_{2}}}}$
				${\displaystyle i_{5}={\tfrac {1}{1+{\tfrac {S_{2}}{R_{2}}}}}}$
Kinetic Ratios
Specific Torque[s] R & 1	${\displaystyle {\tfrac {T_{2;R}}{T_{1;R}}}=-{\tfrac {R_{2}}{S_{2}}}\eta _{0}\left(1+{\tfrac {S_{3}}{R_{3}}}\eta _{0}\right)}$			${\displaystyle {\tfrac {T_{2;1}}{T_{1;1}}}={\tfrac {R_{1}R_{2}}{S_{1}S_{2}}}{\eta _{0}}^{\tfrac {3}{2}}\left(1+{\tfrac {S_{3}}{R_{3}}}\eta _{0}\right)}$
Specific Torque[s] 2 & 3	${\displaystyle {\tfrac {T_{2;2}}{T_{1;2}}}={\tfrac {\left(1+{\tfrac {R_{1}}{S_{1}}}\eta _{0}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\eta _{0}\right)}{1+{\tfrac {S_{2}}{R_{2}}}\cdot {\tfrac {1}{\eta _{0}}}}}}$				${\displaystyle {\tfrac {T_{2;3}}{T_{1;3}}}={\tfrac {1+{\tfrac {R_{1}}{S_{1}}}\eta _{0}}{1+{\tfrac {S_{2}}{R_{2}}}\cdot {\tfrac {1}{\eta _{0}}}}}}$
Specific Torque[s] 4 & 5	${\displaystyle {\tfrac {T_{2;4}}{T_{1;4}}}={\tfrac {1}{1}}}$			${\displaystyle {\tfrac {T_{2;5}}{T_{1;5}}}={\tfrac {1}{1+{\tfrac {S_{2}}{R_{2}}}\cdot {\tfrac {1}{\eta _{0}}}}}}$
^ Revised 16 November 2025 ^ Layout Input and output are on opposite sides Planetary gearset 2 (the outer Ravigneaux gearset) is on the input (turbine) side Input shafts are, if actuated, S1, C1/C2 (the combined carrier of the compound Ravigneaux gearset 1 + 2), and R1/S2 Output shaft is C3 (the carrier of gearset 3) ^ Total Ratio Span (Total Gear/Transmission Ratio) Nominal ${\displaystyle {\frac {i_{1}}{i_{n}}}}$ 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 ^ a b c d e Total Ratio Span (Total Gear/Transmission Ratio) Effective ${\displaystyle {\frac {min(i_{1};|i_{R}|)}{i_{n}}}}$ The span is only effective to the extent that the reverse gear ratio matches that of 1st gear see also Standard R:1 ^ Ratio Span's Center ${\displaystyle (i_{1}i_{n})^{\frac {1}{2}}}$ 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 ${\displaystyle \left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}}$ 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 ^ Sun 3: sun gear of gearset 3 ^ Ring 3: ring gear of gearset 3 ^ a b c d e f g 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 2) is always larger and the upper half of the gear steps (between the large gears; rounded up, here the last 2) 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) ^ a b c d e f 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) see also Total Ratio Span (Total Gear/Transmission Ratio) Effective ^ a b c d 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) ^ a b From large to small gears (from right to left) ^ a b c d 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) ^ a b c d 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) ^ a b c d e f g Specific Torque Ratio And Efficiency The specific torque is the Ratio of output torque ${\displaystyle T_{2;n}}$ to input torque ${\displaystyle T_{1;n}}$ with ${\displaystyle n=gear}$ The efficiency is calculated from the specific torque in relation to the transmission ratio Power loss for single meshing gears is in the range of 1 % to 1.5 % helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range ^ a b c d e f Corridor for specific torque and efficiency in planetary gearsets, the stationary gear ratio ${\displaystyle i_{0}}$ is formed via the planetary gears and thus by two meshes for reasons of simplification, the efficiency for both meshes together is commonly specified there the efficiencies ${\displaystyle \eta _{0}}$ specified here are based on assumed efficiencies for the stationary ratio ${\displaystyle i_{0}}$ of ${\displaystyle \eta _{0}=0.9800}$ (upper value) and ${\displaystyle \eta _{0}=0.9700}$ (lower value) for both interventions together The corresponding efficiency for single-meshing gear pairs is ${\displaystyle {\eta _{0}}^{\frac {1}{2}}}$ at ${\displaystyle 0.9800^{\frac {1}{2}}=0.98995}$ (upper value) and ${\displaystyle 0.9700^{\frac {1}{2}}=0.98489}$ (lower value) ^ a b inner and outer sun gears of the Ravigneaux planetary gearset are inverted ^ Blocks R1 (ring gear of the inner Ravigneaux gearset) and S2 (sun gear of the outer Ravigneaux gearset) ^ Blocks C1 and C2 (the common Ravigneaux carrier 1 + 2) ^ Blocks S3 ^ Connects S1 (the sun of the inner Ravigneaux gearset) with the turbine ^ Couples R1 (the ring gear of the inner Ravigneaux gearset) and S2 (the sun gear of the outer Ravigneaux gearset) with the turbine ^ Connects C1 and C2 (the common Ravigneaux carrier 1 + 2) with the turbine ^ Couples S3 with R3 ^ a b c Ordinary Noted For direct determination of the ratio ^ a b c Elementary Noted Alternative representation for determining the transmission ratio Contains only operands With simple fractions of both central gears of a planetary gearset Or with the value 1 As a basis For reliable And traceable Determination of specific torque and efficiency

With planetary transmissions, the number of gears can be increased conventionally by adding additional gearsets as well as brakes and clutches, or conceptually by switching from serial to combined parallel and serial power flow. The conceptual way requires a computer-aided design. The resulting progress is reflected in a better ratio of the number of gears to the number of components used compared to existing layouts.

The 5HP 30 and 24 are the first transmission family with combined parallel and serial power flow to prevent these transmission from becoming larger, heavier, and more expensive. With 9 main components, it saves 1 component compared to the 5HP 18 and 19 family. No subsequent transmissions from ZF including the 8-speed transmission 8HP require more main components.

Gearset Concept: Cost-Effectiveness^[a]

With Assessment	Output: Gear Ratios	Innovation Elasticity[b] Δ Output : Δ Input	Input: Main Components
			Total	Gearsets	Brakes	Clutches
5HP 30/24 Ref. Object	${\displaystyle n_{O1}}$ ${\displaystyle n_{O2}}$	Topic[b]	${\displaystyle n_{I}=n_{G}+}$ ${\displaystyle n_{B}+n_{C}}$	${\displaystyle n_{G1}}$ ${\displaystyle n_{G2}}$	${\displaystyle n_{B1}}$ ${\displaystyle n_{B2}}$	${\displaystyle n_{C1}}$ ${\displaystyle n_{C2}}$
Δ Number	${\displaystyle n_{O1}-n_{O2}}$		${\displaystyle n_{I1}-n_{I2}}$	${\displaystyle n_{G1}-n_{G2}}$	${\displaystyle n_{B1}-n_{B2}}$	${\displaystyle n_{C1}-n_{C2}}$
Relative Δ	Δ Output ${\displaystyle {\tfrac {n_{O1}-n_{O2}}{n_{O2}}}}$	${\displaystyle {\tfrac {n_{O1}-n_{O2}}{n_{O2}}}:{\tfrac {n_{I1}-n_{I2}}{n_{I2}}}}$ ${\displaystyle ={\tfrac {n_{O1}-n_{O2}}{n_{O2}}}}$·${\displaystyle {\tfrac {n_{I2}}{n_{I1}-n_{I2}}}}$	Δ Input ${\displaystyle {\tfrac {n_{I1}-n_{I2}}{n_{I2}}}}$	${\displaystyle {\tfrac {n_{G1}-n_{G2}}{n_{G2}}}}$	${\displaystyle {\tfrac {n_{B1}-n_{B2}}{n_{B2}}}}$	${\displaystyle {\tfrac {n_{C1}-n_{C2}}{n_{C2}}}}$
5HP 30/24 4HP 14/16/18[c]	5[d] 4[d]	Progress[b]	9 7	3 2[e]	3 2	3 3
Δ Number	1		2	1	1	0
Relative Δ	0.250 ${\displaystyle {\tfrac {1}{4}}}$	0.875[b] ${\displaystyle {\tfrac {1}{4}}:{\tfrac {2}{7}}={\tfrac {1}{4}}}$·${\displaystyle {\tfrac {7}{2}}={\tfrac {7}{8}}}$	0.286 ${\displaystyle {\tfrac {2}{7}}}$	0.500 ${\displaystyle {\tfrac {1}{2}}}$	0.500 ${\displaystyle {\tfrac {1}{2}}}$	0.000 ${\displaystyle {\tfrac {0}{3}}}$
5HP 30/24 4HP 20/22/24[c]	5[d] 4[d]	Progress[b]	9 10	3 3	3 4	3 3
Δ Number	1		-1	0	-1	0
Relative Δ	0.250 ${\displaystyle {\tfrac {1}{4}}}$	−2.500[b] ${\displaystyle {\tfrac {1}{4}}:{\tfrac {-1}{10}}={\tfrac {1}{4}}}$·${\displaystyle {\tfrac {10}{-1}}={\tfrac {10}{-4}}}$	−0.100 ${\displaystyle {\tfrac {-1}{10}}}$	0.000 ${\displaystyle {\tfrac {0}{3}}}$	−0.250 ${\displaystyle {\tfrac {-1}{4}}}$	0.000 ${\displaystyle {\tfrac {0}{3}}}$
5HP 30/24 3-Speed[f]	5[d] 3[d]	Market Position[b]	9 7	3 2[e]	3 3	3 2
Δ Number	2		2	1	0	1
Relative Δ	0.667 ${\displaystyle {\tfrac {2}{3}}}$	2.333[b] ${\displaystyle {\tfrac {2}{3}}:{\tfrac {2}{7}}={\tfrac {2}{3}}}$·${\displaystyle {\tfrac {7}{2}}={\tfrac {7}{3}}}$	0.286 ${\displaystyle {\tfrac {2}{7}}}$	0.500 ${\displaystyle {\tfrac {1}{2}}}$	0.000 ${\displaystyle {\tfrac {0}{3}}}$	0.500 ${\displaystyle {\tfrac {1}{2}}}$
^ Progress increases cost-effectiveness and is reflected in the ratio of forward gears to main components. It depends on the power flow: parallel: using the two degrees of freedom of planetary gearsets to increase the number of gears with unchanged number of components serial: in-line combined planetary gearsets without using the two degrees of freedom to increase the number of gears a corresponding increase in the number of components is unavoidable ^ a b c d e f g h Innovation Elasticity Classifies Progress And Market Position Automobile manufacturers drive forward technical developments primarily in order to remain competitive or to achieve or defend technological leadership. This technical progress has therefore always been subject to economic constraints Only innovations whose relative additional benefit is greater than the relative additional resource input, i.e. whose economic elasticity is greater than 1, are considered for realization The required innovation elasticity of an automobile manufacturer depends on its expected return on investment. The basic assumption that the relative additional benefit must be at least twice as high as the relative additional resource input helps with orientation negative, if the output increases and the input decreases, is perfect 2 or above is good 1 or above is acceptable (red) below this is unsatisfactory (bold) ^ a b Direct Predecessor To reflect the progress of the specific model change ^ a b c d e f plus 1 reverse gear ^ a b of which 2 gearsets are combined as a compound Ravigneaux gearset ^ Reference Standard (Benchmark) 3-speed transmissions with torque converters have established the modern market for automatic transmissions and thus made it possible in the first place, as this design proved to be a particularly successful compromise between cost and performance It became the archetype and dominated the world market for around 3 decades, setting the standard for automatic transmissions. It was only when fuel consumption became the focus of interest that this design reached its limits, which is why it has now completely disappeared from the market What has remained is the orientation that it offers as a reference standard (point of reference, benchmark) for this market for determining progressiveness and thus the market position of all other, later designs All transmission variants consist of 7 main components Typical examples are Turbo-Hydramatic from GM Cruise-O-Matic from Ford TorqueFlite from Chrysler Detroit Gear from BorgWarner for Studebaker BW-35 from BorgWarner and as T35 from Aisin 3N 71 from Nissan/Jatco 3 HP from ZF Friedrichshafen W3A 040 and W3B 050 from Mercedes-Benz

The main objective in replacing the predecessor model was to improve vehicle fuel economy with extra speeds and a wider gear span to allow the engine speed level to be lowered (downspeeding).

Gear Ratio Analysis

In-Depth Analysis With Assessment[a]		Planetary Gearset: Teeth[b]			Count	Nomi- nal[c] Effec- tive[d]	Cen- ter[e]
		Simpson		Simple			Avg.[f]
Model Type	Version First Delivery	S1[g] R1[h]	S2[i] R2[j]	S3[k] R3[l]	Brakes Clutches	Ratio Span	Gear Step[m]
Gear Ratio	R ${\displaystyle {i_{R}}}$		1 ${\displaystyle {i_{1}}}$	2 ${\displaystyle {i_{2}}}$	3 ${\displaystyle {i_{3}}}$	4 ${\displaystyle {i_{4}}}$	5 ${\displaystyle {i_{5}}}$
Step[m]	${\displaystyle -{\frac {i_{R}}{i_{1}}}}$[n]		${\displaystyle {\frac {i_{1}}{i_{1}}}}$	${\displaystyle {\frac {i_{1}}{i_{2}}}}$[o]	${\displaystyle {\frac {i_{2}}{i_{3}}}}$	${\displaystyle {\frac {i_{3}}{i_{4}}}}$	${\displaystyle {\frac {i_{4}}{i_{5}}}}$
Δ Step[p][q]				${\displaystyle {\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}}$	${\displaystyle {\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}}$	${\displaystyle {\tfrac {i_{3}}{i_{4}}}:{\tfrac {i_{4}}{i_{5}}}}$	${\displaystyle {\tfrac {i_{4}}{i_{5}}}:{\tfrac {i_{5}}{i_{6}}}}$
Shaft Speed	${\displaystyle {\frac {i_{1}}{i_{R}}}}$		${\displaystyle {\frac {i_{1}}{i_{1}}}}$	${\displaystyle {\frac {i_{1}}{i_{2}}}}$	${\displaystyle {\frac {i_{1}}{i_{3}}}}$	${\displaystyle {\frac {i_{1}}{i_{4}}}}$	${\displaystyle {\frac {i_{1}}{i_{5}}}}$
Δ Shaft Speed[r]	${\displaystyle 0-{\tfrac {i_{1}}{i_{R}}}}$		${\displaystyle {\tfrac {i_{1}}{i_{1}}}-0}$	${\displaystyle {\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{5}}}-{\tfrac {i_{1}}{i_{4}}}}$
Specific Torque[s]	${\displaystyle {\tfrac {T_{2;R}}{T_{1;R}}}}$[t]		${\displaystyle {\tfrac {T_{2;1}}{T_{1;1}}}}$[t]	${\displaystyle {\tfrac {T_{2;2}}{T_{1;2}}}}$[t]	${\displaystyle {\tfrac {T_{2;3}}{T_{1;3}}}}$[t]	${\displaystyle {\tfrac {T_{2;4}}{T_{1;4}}}}$[t]	${\displaystyle {\tfrac {T_{2;5}}{T_{1;5}}}}$[t]
Efficiency ${\displaystyle \eta _{n}}$[s]	${\displaystyle {\tfrac {T_{2;R}}{T_{1;R}}}:{i_{R}}}$		${\displaystyle {\tfrac {T_{2;1}}{T_{1;1}}}:{i_{1}}}$	${\displaystyle {\tfrac {T_{2;2}}{T_{1;2}}}:{i_{2}}}$	${\displaystyle {\tfrac {T_{2;3}}{T_{1;3}}}:{i_{3}}}$	${\displaystyle {\tfrac {T_{2;4}}{T_{1;4}}}:{i_{4}}}$	${\displaystyle {\tfrac {T_{2;5}}{T_{1;5}}}:{i_{5}}}$
5HP 30	560 N⋅m (413 lb⋅ft) 1992	40 100	32 108	38 97	3 3	4.5169 4.5169 [d][n]	1.6716
							1.4578 [m]
Gear Ratio	−3.6842 ${\displaystyle -{\tfrac {70}{19}}}$		3.5526 ${\displaystyle {\tfrac {135}{38}}}$	2.2436 ${\displaystyle {\tfrac {175}{78}}}$	1.5449[m][q] ${\displaystyle {\tfrac {275}{178}}}$	1.0000[m] ${\displaystyle {\tfrac {1}{1}}}$	0.7865[r] ${\displaystyle {\tfrac {70}{89}}}$
Step	1.0370		1.0000	1.5835	1.4522[m]	1.5449[m]	1.2714
Δ Step[p]				1.0904	0.9400[q]	1.2151
Speed	–0.9643		1.0000	1.5835	2.2995	3.5526	4.5169
Δ Speed	0.9643		1.0000	0.5835	0.7161	1.2531	0.9643[r]
Specific Torque[s]	–3.5078 –3.4217		3.5016 3.4761	2.2059 2.1870	1.5272 1.5183	1.0000	0.7782 0.7738
Efficiency ${\displaystyle \eta _{n}}$[s]	0.9521 0.9288		0.9856 0.9784	0.9832 0.9748	0.9885 0.9827	1.0000	0.9894 0.9839
5HP 24	440 N⋅m (325 lb⋅ft) 1996	36 93	32 100	35 90	3 3	4.4435 4.4435[d][n]	1.6943
							1.4519[m]
Gear Ratio	−4.0952[n][d] ${\displaystyle -{\tfrac {86}{21}}}$		3.5714 ${\displaystyle {\tfrac {25}{7}}}$	2.2000 ${\displaystyle {\tfrac {11}{5}}}$	1.5047[q] ${\displaystyle {\tfrac {161}{107}}}$	1.0000[m] ${\displaystyle {\tfrac {1}{1}}}$	0.8037[r] ${\displaystyle {\tfrac {86}{107}}}$
Step	1.1467[n]		1.0000	1.6234	1.4621	1.5047[m]	1.2419
Δ Step[p]				1.1103	0.9717[q]	1.2094
Speed	-0.8721		1.0000	1.6234	2.3736	3.5714	4.4435
Δ Speed	0.8721		1.0000	0.6234	0.7502	1.1979	0.8721[r]
Specific Torque[s]	–3.8985 –3.8025		3.5200 3.4943	2.1630 2.1445	1.4880 1.4795	1.0000	0.7959 0.7918
Efficiency ${\displaystyle \eta _{n}}$[s]	0.9520 0.9285		0.9856 0.9784	0.9832 0.9748	0.9889 0.9833	1.0000	0.9902 0.9851
Actuated Shift Elements
Brake A[u]					❶		❶
Brake B[v]				❶
Brake C[w]	❶		❶
Clutch D[x]			❶	❶	❶	❶
Clutch E[y]						❶	❶
Clutch F[z]	❶
Geometric Ratios
Ratio R & 2 Ordinary[aa] Elementary Noted[ab]	${\displaystyle i_{R}=-{\frac {S_{2}(S_{1}+R_{1})(S_{3}+R_{3})}{S_{1}R_{2}S_{3}}}}$			${\displaystyle i_{2}={\frac {(S_{2}+R_{2})(S_{3}+R_{3})}{S_{2}R_{3}+S_{3}(S_{2}+R_{2})}}}$
	${\displaystyle i_{R}=-{\tfrac {S_{2}}{R_{2}}}\left(1+{\tfrac {R_{1}}{S_{1}}}\right)\left(1+{\tfrac {R_{3}}{S_{3}}}\right)}$			${\displaystyle i_{2}={\tfrac {1}{{\tfrac {1}{1+{\tfrac {R_{3}}{S_{3}}}}}+{\tfrac {1}{\left(1+{\tfrac {R_{2}}{S_{2}}}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\right)}}}}}$
Ratio 1 & 5 Ordinary[aa] Elementary Noted[ab]	${\displaystyle i_{1}={\frac {S_{3}+R_{3}}{S_{3}}}}$		${\displaystyle i_{5}={\frac {S_{2}(S_{1}+R_{1})(S_{3}+R_{3})}{S_{2}(S_{1}+R_{1})(S_{3}+R_{3})+S_{1}R_{2}S_{3}}}}$
	${\displaystyle i_{1}=1+{\tfrac {R_{3}}{S_{3}}}}$		${\displaystyle i_{5}={\tfrac {1}{1+{\tfrac {\tfrac {R_{2}}{S_{2}}}{\left(1+{\tfrac {R_{1}}{S_{1}}}\right)\left(1+{\tfrac {R_{3}}{S_{3}}}\right)}}}}}$
Ratio 3 & 4 Ordinary[aa] Elementary Noted[ab]	${\displaystyle i_{3}={\frac {(S_{1}(S_{2}+R_{2})+R_{1}S_{2})(S_{3}+R_{3})}{S_{2}(S_{1}+R_{1})(S_{3}+R_{3})+S_{1}R_{2}S_{3}}}}$					${\displaystyle i_{4}={\frac {1}{1}}}$
	${\displaystyle i_{3}={\tfrac {1}{{\tfrac {1}{{\tfrac {1}{1+{\tfrac {S_{1}}{R_{1}}}}}+{\tfrac {1+{\tfrac {R_{2}}{S_{2}}}}{1+{\tfrac {R_{1}}{S_{1}}}}}}}+{\tfrac {1}{\left(1+{\tfrac {S_{2}}{R_{2}}}\left(1+{\tfrac {R_{1}}{S_{1}}}\right)\right)\left(1+{\tfrac {R_{3}}{S_{3}}}\right)}}}}}$
Kinetic Ratios
Specific Torque[s] R & 1	${\displaystyle {\tfrac {T_{2;R}}{T_{1;R}}}=-{\tfrac {S_{2}}{R_{2}}}\eta _{0}\left(1+{\tfrac {R_{1}}{S_{1}}}\eta _{0}\right)\left(1+{\tfrac {R_{3}}{S_{3}}}\eta _{0}\right)}$				${\displaystyle {\tfrac {T_{2;1}}{T_{1;1}}}=1+{\tfrac {R_{3}}{S_{3}}}\eta _{0}}$
Specific Torque[s] 2 & 5	${\displaystyle {\tfrac {T_{2;2}}{T_{1;2}}}={\tfrac {1}{{\tfrac {1}{1+{\tfrac {R_{3}}{S_{3}}}\eta _{0}}}+{\tfrac {1}{\left(1+{\tfrac {R_{2}}{S_{2}}}\eta _{0}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\eta _{0}\right)}}}}}$				${\displaystyle {\tfrac {T_{2;5}}{T_{1;5}}}={\tfrac {1}{1+{\tfrac {{\tfrac {R_{2}}{S_{2}}}\cdot {\tfrac {1}{\eta _{0}}}}{\left(1+{\tfrac {R_{1}}{S_{1}}}\eta _{0}\right)\left(1+{\tfrac {R_{3}}{S_{3}}}\eta _{0}\right)}}}}}$
Specific Torque[s] 3 & 4	${\displaystyle {\tfrac {T_{2;3}}{T_{1;3}}}={\tfrac {1}{{\tfrac {1}{{\tfrac {1}{1+{\tfrac {S_{1}}{R_{1}}}\cdot {\tfrac {1}{{\eta _{0}}^{\tfrac {1}{3}}}}}}+{\tfrac {1+{\tfrac {R_{2}}{S_{2}}}{\eta _{0}}^{\tfrac {1}{2}}}{1+{\tfrac {R_{1}}{S_{1}}}\cdot {\tfrac {1}{{\eta _{0}}^{\tfrac {1}{3}}}}}}}}+{\tfrac {1}{\left(1+{\tfrac {S_{2}}{R_{2}}}{\eta _{0}}^{\tfrac {1}{2}}\left(1+{\tfrac {R_{1}}{S_{1}}}{\eta _{0}}^{\tfrac {1}{3}}\right)\right)\left(1+{\tfrac {R_{3}}{S_{3}}}\eta _{0}\right)}}}}}$						${\displaystyle {\tfrac {T_{2;4}}{T_{1;4}}}={\tfrac {1}{1}}}$
^ Revised 16 November 2025 ^ Layout Input and output are on opposite sides Planetary gearset 1 is on the input (turbine) side Input shafts are, if actuated, S1, C2, S3, and R1 Output shaft is C3 (the carrier of gearset 3) ^ Total Ratio Span (Total Gear/Transmission Ratio) Nominal ${\displaystyle {\frac {i_{1}}{i_{n}}}}$ 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 ^ a b c d Total Ratio Span (Total Gear/Transmission Ratio) Effective ${\displaystyle {\frac {min(i_{1};|i_{R}|)}{i_{n}}}}$ The span is only effective to the extent that the reverse gear ratio matches that of 1st gear see also Standard R:1 ^ Ratio Span's Center ${\displaystyle (i_{1}i_{n})^{\frac {1}{2}}}$ 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 ${\displaystyle \left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}}$ With decreasing step width the gears connect better to each other shifting comfort increases ^ Sun 1: sun gear of gearset 1 ^ Ring 1: ring gear of gearset 1 ^ Sun 2: sun gear of gearset 2 ^ Ring 2: ring gear of gearset 2 ^ Sun 3: sun gear of gearset 3 ^ Ring 3: ring gear of gearset 3 ^ a b c d e f g h i j 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 2) is always larger and the upper half of the gear steps (between the large gears; rounded up, here the last 2) 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) ^ a b c d e 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) see also Total Ratio Span (Total Gear/Transmission Ratio) Effective ^ 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) ^ a b c From large to small gears (from right to left) ^ a b c d e 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) ^ a b c d e 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) ^ a b c d e f g h i Specific Torque Ratio And Efficiency The specific torque is the Ratio of output torque ${\displaystyle T_{2;n}}$ to input torque ${\displaystyle T_{1;n}}$ with ${\displaystyle n=gear}$ The efficiency is calculated from the specific torque in relation to the transmission ratio Power loss for single meshing gears is in the range of 1 % to 1.5 % helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range ^ a b c d e f Corridor for specific torque and efficiency in planetary gearsets, the stationary gear ratio ${\displaystyle i_{0}}$ is formed via the planetary gears and thus by two meshes for reasons of simplification, the efficiency for both meshes together is commonly specified there the efficiencies ${\displaystyle \eta _{0}}$ specified here are based on assumed efficiencies for the stationary ratio ${\displaystyle i_{0}}$ of ${\displaystyle \eta _{0}=0.9800}$ (upper value) and ${\displaystyle \eta _{0}=0.9700}$ (lower value) for both interventions together The corresponding efficiency for single-meshing gear pairs is ${\displaystyle {\eta _{0}}^{\tfrac {1}{2}}}$ at ${\displaystyle 0.9800^{\tfrac {1}{2}}=0.98995}$ (upper value) and ${\displaystyle 0.9700^{\tfrac {1}{2}}=0.98489}$ (lower value) ^ Blocks S1 ^ Blocks C1 (the carrier of gearset 1) ^ Blocks R3 ^ Connects S2 and S3 with the turbine ^ Connects R1 with the turbine ^ Connects C1 with the turbine ^ a b c Ordinary Noted For direct determination of the ratio ^ a b c Elementary Noted Alternative representation for determining the transmission ratio Contains only operands With simple fractions of both central gears of a planetary gearset Or with the value 1 As a basis For reliable And traceable Determination of specific torque and efficiency