GM 8L90 transmission

8L90
8L90
Overview
Manufacturer	General Motors
Production	2014–present
Body and chassis
Class	8-speed longitudinal automatic transmission
Related	GM 8L45; ZF 8HP
Chronology
Predecessor	6L80
Successor	GM 10L80 · 10L90 · 10L1000

The 8L90 is an eight-speed automatic transmission built by General Motors. It is designed for use in longitudinal engine applications either attached to the front-located engine[1] with a standard bell housing or in the rear of the car adjacent to the differential (as in the Corvette). It is a hydraulic (hydramatic) design. GM also produces a similar design with the smaller 8L45.

The 8L90 is the subject of a class-action lawsuit filed in December 2018 that alleges the transmission suffers from persistent "shudder" issues and that GM has known about the problems since its introduction and has failed to provide a solution, instead choosing to wait until the unit is out of warranty.[2]

Specifications

Gear Teeth and Ratios[3]			Planetary Gearset: Teeth				Count	Total	Avg.

Model Type	Version First Delivery		Sun 1 ${S_{1}}$ Ring 1 ${R_{1}}$	Sun 2 ${S_{2}}$ Ring 2 ${R_{2}}$	Sun 3 ${S_{3}}$ Ring 3 ${R_{3}}$	Sun 4 ${S_{4}}$ Ring 4 ${R_{4}}$	Brakes Clutches	Ratio Span	Gear Step
Gear	R	1	2	3	4	5	6	7	8

8L90 M5U	900 N⋅m (664 lb⋅ft)[4] 2014		41[5] 79	46 86	37 73	25 89	2 3	6.9991	1.3204
Ratio	–3.8176	4.5600	2.9709	2.0751	1.6876	1.2700	1.0000	0.8455	0.6515

8L45 M5T	550 N⋅m (406 lb⋅ft) 2015		41 79	41 79	41 79	26 94	2 3	7.0107	1.3208
Ratio	–3.9278	4.6154	3.0385	2.0648	1.6583	1.2587	1.0000	0.8494	0.6583

Ratio R & even	${\tfrac {R_{2}(S_{3}S_{4}-R_{3}R_{4})}{S_{3}S_{4}(S_{2}+R_{2})}}$		${\tfrac {R_{2}(S_{4}+R_{4})}{(S_{2}+R_{2})S_{4}}}$		$1+{\tfrac {S_{2}R_{1}}{S_{1}(S_{2}+R_{2})}}$		${\tfrac {1}{1}}$		${\tfrac {R_{2}}{S_{2}+R_{2}}}$
Ratio odd		${\tfrac {S_{4}+R_{4}}{S_{4}}}$	${\tfrac {(S_{1}+R_{1})(S_{4}+R_{4})}{S_{4}R_{1}+S_{1}(S_{4}+R_{4})}}$		${\tfrac {S_{1}R_{2}R_{4}(S_{3}+R_{3})+S_{2}S_{3}(S_{1}+R_{1})(S_{4}+R_{4})}{S_{1}R_{4}(S_{3}(S_{2}+R_{2})+R_{2}R_{3})+S_{2}S_{3}S_{4}(S_{1}+R_{1})}}$			${\tfrac {R_{2}(S_{3}+R_{3})}{R_{2}(S_{3}+R_{3})+S_{2}S_{3}}}$

Applications

Model years	Make and model	Final drive ratio
2015–2017	Cadillac Escalade[6]	3.23
2015–2019	Chevrolet Corvette (C7) Stingray[7]	2.41 (std)
2015–2019	Chevrolet Corvette (C7) Stingray[7]	2.73 (Z51)
2015–2019	Chevrolet Corvette (C7) Z06[8]	2.41
2015–present	Chevrolet Silverado/GMC Sierra[9]	3.23 (std.)
2015–present	Chevrolet Silverado/GMC Sierra[9]	3.42 (Max Trailering Package)
2015–2017	GMC Yukon Denali/Denali XL	3.23
2016–present	Cadillac ATS-V	2.85
2016–present	Cadillac CTS-V	2.85
2016–present	Cadillac CT6	3.27
2016–2018	Chevrolet Camaro	2.77
2017–present	Chevrolet Express/GMC Savana (2.8L diesel engine/4.3L gas engine only)
2015–present	Chevrolet Colorado/GMC Canyon	3.42

References

"USA Information Guide Model Year 2018" (PDF). Retrieved 15 July 2019.
"Class Action Lawsuit Filed Over Alleged Shifting Defect in Certain General Motors Transmissions". 19 December 2018. Retrieved 2 February 2019.
"New 8-Speed Enables Quicker, More Efficient Corvette". www.gm.com. General Motors. 20 August 2014. Archived from the original on 22 December 2014. Retrieved 21 August 2014.
"Transmission Repair Cost Guide". Retrieved 15 July 2019.
"WIT · Whatever It Takes · Automatic Transmission Parts Catalog 2018+2019 Page 268". Retrieved 15 July 2019.
"2015 Cadillac Escalade Updated with 8L90 8-Speed Automatic and More Tech [Photo Gallery]". 11 August 2014. Retrieved 12 August 2014.
"Chevrolet Confirms 2015 Corvette Stingray To Utilize 8L90 Eight-Speed Gearbox". Retrieved 9 April 2014.
"Supercharged 2015 Chevy Corvette Z06 takes the C7 beyond the ZR1 [w/video]". Retrieved 25 January 2014.
"GM confirms 2015 Silverado, Sierra to get 8-speed automatic". Retrieved 18 June 2014.

External links

General Motors Powertrain Division

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.

[1] "USA Information Guide Model Year 2018" (PDF). Retrieved 15 July 2019.

[2] "Class Action Lawsuit Filed Over Alleged Shifting Defect in Certain General Motors Transmissions". 19 December 2018. Retrieved 2 February 2019.

[3] "New 8-Speed Enables Quicker, More Efficient Corvette". www.gm.com. General Motors. 20 August 2014. Archived from the original on 22 December 2014. Retrieved 21 August 2014.

[4] "Transmission Repair Cost Guide". Retrieved 15 July 2019.

[5] "WIT · Whatever It Takes · Automatic Transmission Parts Catalog 2018+2019 Page 268". Retrieved 15 July 2019.

[6] "2015 Cadillac Escalade Updated with 8L90 8-Speed Automatic and More Tech [Photo Gallery]". 11 August 2014. Retrieved 12 August 2014.

[7] "Chevrolet Confirms 2015 Corvette Stingray To Utilize 8L90 Eight-Speed Gearbox". Retrieved 9 April 2014.

[8] "Supercharged 2015 Chevy Corvette Z06 takes the C7 beyond the ZR1 [w/video]". Retrieved 25 January 2014.

[9] "GM confirms 2015 Silverado, Sierra to get 8-speed automatic". Retrieved 18 June 2014.

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