ZF 9HP transmission

9HP is ZF Friedrichshafen AG's trademark name for its nine-speed automatic transmission models (9-speed transmission with Hydraulic converter and Planetary gearsets) for transverse engine applications, designed by ZF's subsidiary in Saarbrücken and build in Gray Court, South Carolina.[1] It is used in front-wheel drive and all-wheel drive vehicles.

ZF 9HP
Overview
ManufacturerZF Friedrichshafen
Production2013–
AssemblyGray Court, South Carolina, United States
Body and chassis
Class9-speed transverse automatic transmission

Abstract

Land Rover and Jeep demonstrated the world's first nine-speed automatic transmissions for passenger cars at the 2013 Geneva Motor Show.[2] The 2014 Jeep Cherokee featured the world's first nine-speed automatic transmission for a passenger vehicle to market.

Specifications

Basic Concept

The 9HP is only 0.24 inches (6mm) longer than, and weighs 16.5 lbs (7.5 kg) less than, the outgoing six-speed transmission. The compact packaging is achieved by using a number of innovative design features: a new compact hydraulic vane-type pump, two patented dog clutches, which replace bulkier conventional clutch packs, and a nested gear set.[2] ZF claims that it is able to save an average of 16% in fuel compared with current 6-speed automatic transmissions. The gear ratio spread is 9.8364:1. The transmission has a torque range between 280 and 480 Nm.[1]

Technical Data
Gear Teeth and Ratios Planetary Gearset: Teeth Count Total Avg.
Model Version First

Delivery

 Sun 4

Ring 4

 Sun 3

Ring 3

 Sun 2

Ring 2

 Sun 1

Ring 1

 Brakes

Clutches

 Ratio

Span

 Gear

Step

Gear 1 2 3 4 5 6 7 8 9 R
9HP 28

9HP 48

 280 Nm · 207 lb·ft

480 Nm · 354 lb·ft

 2013

2013

 42

110

 42

110

 94

138

 54

110

 3[lower-alpha 1]

3[lower-alpha 2]

 9.8364 1.3308
Ratio 4.7126 2.8468 1.9094 1.3818 1.0000 0.8076 0.6991 0.5802 0.4791 - 3.8008

How It Works

An Animated Drive Line Schematic & A Rotational Speeds Nomogram

These ordinates are positioned on the abscissa in strict accordance with the proportions of the sun gears' teeth numbers relative to those of their rings. Consequently, the output ratios on the ordinate C4 (carrier of the last planetary gearset RS4) follows closely to those of the actual transmission. Note that elements A and F are labelled interchanged (cf. legend below).

9HP Nomogram
Concentric Planetary gearset - Simpson Planetary gearset

▶️ Interactive Nomogram

This interactive nomogram is a real geometric calculator exactly representing the rotational speeds of the transmission's 3x4 = 12 internal shafts for each of its 9 ratios (+ reverse), grouped according to their 5 permanent coupling on 4 joint ordinates and 3 independent ordinates. These ordinates are positioned on the abscissa in strict accordance with the proportions of the sun gears' teeth numbers relative to those of their rings. Consequently, the output ratios on the 6th ordinate (carrier of the fourth planetary gearset) follows closely those of the actual transmission. This advantageous geometric construction sets us free from Willis' famous and tedious formula, because all calculations are exclusively determined by lengths ratios, respectively teeth numbers on the abscissa for the 4 epicyclic ratios, and of rotational speeds on the 6th ordinate for the 10 gear ratios.

Legend:
A : Dog Clutch (couples r1+s2 with input shaft)
B : Clutch (couples s1 with input shaft)
C : Brake (blocks s1 sun gear)
D : Brake (blocks r2 ring gear)
E : Clutch (couples c3+r4 with input shaft)
F : Dog Brake (blocks s3+s4 sun gears)

List of ZF 9HP variants
Name Weight Max. gasoline torque (N·m) Max. diesel torque (N·m) Application examples
9HP28 78 kg 280 280
9HP48 86 kg 480 450 Acura TLX, Acura MDX, Chrysler 200, Chrysler Pacifica (2017– gas versions only), Fiat Doblò, Fiat 500X, Honda Pilot, Honda Odyssey, Honda Passport, Jeep Cherokee (KL), Jeep Renegade, Ram ProMaster City, Range Rover Evoque, Land Rover Discovery Sport, Jaguar E-Pace

Applications

Acura
  • TLX (V6 models, 2015-2020)
  • MDX (2016-2020, non-hybrid models)

Chrysler

FIAT

Opel/Vauxhall

Honda

Jeep

Ram Trucks

Land Rover

Jaguar

Nissan

Technical Imperfections

The transmission has been problematic, as customers of Jeep, Chrysler, and Acura models equipped with the transmission have experienced problems in their vehicles regarding slow shifting and noisy operation. ZF has said this is due to software problems, not mechanical issues.[6]

Chrysler issued Technical Service Bulletins (TSB) for the 2014 Jeep Cherokee to "fix rough and delayed gearshifts", and Acura has issued transmission-related recalls for the 2015 Acura TLX.[7][8]

Also, some sources report problems with the A: Dog Clutch, namely its rapid wear.[9]

Production

Production of the 9HP started in 2013 at ZF's Gray Court facility in Laurens, South Carolina. 400,000 units are produced per year.[10]

Production of the 9HP for Fiat and Chrysler vehicles began in May 2013 at Indiana Transmission Plant I (ITPI), followed by Tipton Transmission Plant in Tipton County, Indiana in May 2014.[11]

Notes
  1. Thereof 1 dog break
  2. Thereof 1 dog clutch

See also

References
  1. "ZF Develops 9-Speed Automatic Transmission for Passenger Cars".
  2. "Land Rover uses the 9-speed automatic transmission by ZF".
  3. "HONDA British-built CR-V refreshed for 2015".
  4. "World Premiere in Geneva: Land Rover installs the world's first 9-speed automatic passenger car transmission from ZF".
  5. https://www.caranddriver.com/news/a35341342/2022-nissan-pathfinder-revealed/
  6. "Holy Shift ZF 9 Speed Automatic Problems Mount Chrysler Releases Third Software Update for Jeep Cherokee".
  7. "Short Shirt Jeep Cherokee 9 Speed Automatic Gets Second Update for Rough Shifting".
  8. "Acura TLX Shifting Problems".
  9. "ZF 9HP48 (948TE) problems".
  10. "Spotted: ZF testing the 9HP Hybrid transmission".
  11. Chrysler Group Dedicates New Plant and Launches Nine-Speed Production in Tipton, Ind.
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