GM 8L transmission
8L 45 · 8L 90 | |
---|---|
Overview | |
Manufacturer | General Motors |
Production | 2014– |
Body and chassis | |
Class | 8-speed longitudinal automatic transmission |
Related | ZF 8HP |
Chronology | |
Predecessor | 6L 45 · 6L 50 · 6L 80 · 6L 90 |
Successor | 10L 80 · 10L 90 · 10L 1000 |
The Hydramatic 8L 45 is an eight-speed automatic transmission built by General Motors debuting in the 2016 Cadillac CT6. It is designed for use in longitudinal engine applications attached to the front-located engine[1] with a standard bell housing. It is a hydraulic (hydramatic) design sharing much with the 8L 90 transmission.[2] Estimated weight savings over the heavier duty 8L 90 is 33 lb (15 kg). Gear ratios used enable a wide 7.0 ratio spread.
The 8L 90 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 8L 45.
Both gearboxes are based on the layout of the ZF 8HP transmission from 2008, with the only difference being that gearsets 1 and 3 are swapped.[3]
Specifications
[edit]Gear Model
|
R | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | Total Span |
Avg. Step |
Compo- nents |
---|---|---|---|---|---|---|---|---|---|---|---|---|
8L 45 · M5N · 2015 | −3.928 | 4.615 | 3.038 | 2.065 | 1.658 | 1.259 | 1.000 | 0.849 | 0.658 | 7.011 | 1.321 | 4 Gearsets 2 Brakes 3 Clutches |
8L 90 · M5U · 2014 | −3.818 | 4.560 | 2.971 | 2.075 | 1.688 | 1.270 | 1.000 | 0.845 | 0.652 | 6.999 | 1.320 | |
ZF 8HP All · 2008[b] | −3.297 | 4.696 | 3.130 | 2.104 | 1.667 | 1.285 | 1.000 | 0.839 | 0.667 | 7.043 | 1.322 |
8L 45 M5N[5] | 8L 90 M5U · N8X[6] | |
---|---|---|
Input Capacity | ||
Maximum engine power | 308 bhp (230 kW)[a] | 420 bhp (313 kW)[b] |
Maximum gearbox torque | 550 N⋅m (406 lb⋅ft)[a] | 900 N⋅m (664 lb⋅ft)[b] |
Maximum shift speed | 7,500/min | 6,000/min |
Vehicle | ||
Maximum Validated Weight Gross Vehicle Weight · GVW |
— | — |
Maximum Validated Weight Gross Curb Vehicle Weight · GCVW |
12,000 lb (5,440 kg)[a] | 22,500 lb (10,210 kg)[b] |
Structure | ||
Range-selector quadrant | P · R · N · D · M · L | |
Case description | 2-piece main, bell integrated with main | |
Case material | Die cast aluminum | |
Shift pattern (2) | 2 on/off solenoids | |
Shift quality | 6 Variable Force Solenoids · 1 for each clutch · 1 for TCC | |
Torque converter clutch | Variable Force Solenoid ECCC · 2 path · turbine damper | |
Converter size | 238 mm (9.37 in) | 258 mm (10.16 in) |
Fluid type | DEXRON High Performance ATF | |
Fluid capacity | 10.8 L (11.4 US qt)[a] | 10.3 L (10.9 US qt)[b] |
Weight | 80 kg (176 lb)[a] | 98.9 kg (218 lb)[b] |
Available Control Features | ||
Shift Patterns | Multiple (Selectable) | |
Driver Shift Control | Tap Up and Down | |
Additional Modes | Tow & Haul Mode (Selectable) | |
Engine Torque Management | On All Shifts | |
Shift Control | Automatic Start/Stop Automatic Grade Braking | |
Assembly sites | GMPT[c] Toledo · Ohio · USA GMPT[c] Silao · Mexico | |
With Assessment | Planetary Gearset: Teeth[a] | Count | Total | Avg. | ||||||
---|---|---|---|---|---|---|---|---|---|---|
Model Type |
Max. Input Torque First Delivery |
S1[b] R1[c] |
S2[d] R2[e] |
S3[f] R3[g] |
S4[h] R4[i] |
Brakes Clutches |
Ratio Span |
Gear Step[j] | ||
Gear Ratio |
R |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 | |
Step | [k] | [l] | ||||||||
Step 2[m] | ||||||||||
Shaft Speed |
||||||||||
Δ Shaft Speed |
||||||||||
8L 45 M5N |
550 N⋅m (406 lb⋅ft) 2015[n] |
41 79 |
41 79 |
41 79 |
26 94 |
2 3 |
7.0107 | 1.3208[j] | ||
Gear Ratio |
−3.9278[k] |
4.6154 |
3.0385[o] |
2.0648 |
1.6583[j][o][p] |
1.2587[o] |
1.0000 |
0.8494[o][p] |
0.6583 | |
Step | 0.8510[k] | 1.0000 | 1.5190 | 1.4715 | 1.2451[j] | 1.3175 | 1.2587 | 1.1773 | 1.2902 | |
Step 2[m] | 1.0322[o] | 1.1819 | 0.9450[o] | 1.0468[o] | 1.0691 | 0.9125[o] | ||||
Speed | –1.1751 | 1.0000 | 1.5190 | 2.2353 | 2.7831 | 3.6669 | 4.6154 | 5.4338 | 7.0107 | |
Δ Speed | 1.1751 | 1.0000 | 0.5190 | 0.7163 | 0.5479[p] | 0.8837 | 0.9485 | 0.8184[p] | 1.5769 | |
8L 90 M5U |
900 N⋅m (664 lb⋅ft)[7] 2014[q] |
41[8] 79 |
46 86 |
37 73 |
25 89 |
2 3 |
6.9991 | 1.3204[j] | ||
Gear Ratio |
−3.8176[k] |
4.5600 |
2.9709[o] |
2.0751 |
1.6876[j][o][p] |
1.2700[o] |
1.0000 |
0.8455[o][p] |
0.6515 | |
Step | 0.8372[k] | 1.0000 | 1.5349 | 1.4317 | 1.2297[j] | 1.3288 | 1.2700 | 1.1828 | 1.2977 | |
Step 2[m] | 1.0721[o] | 1.1643 | 0.9254[o] | 1.0463[o] | 1.0738 | 0.9114[o] | ||||
Speed | –1.1945 | 1.0000 | 1.5349 | 2.1975 | 2.7021 | 3.5905 | 4.56 | 5.3933 | 6.9991 | |
Δ Speed | 1.1945 | 1.0000 | 0.5349 | 0.6626 | 0.5047[p] | 0.8884 | 0.9695 | 0.8333[p] | 1.6057 | |
Ratio[r] R & even |
||||||||||
Ratio[r] odd |
||||||||||
Algebra And Actuated Shift Elements[s] | ||||||||||
Brake A[t] | ❶ | ❶ | ❶ | ❶ | ❶ | |||||
Brake B[u] | ❶ | ❶ | ❶ | ❶ | ❶ | ❶ | ||||
Clutch C[v] | ❶ | ❶ | ❶ | ❶ | ❶ | |||||
Clutch D[w] | ❶ | ❶ | ❶ | ❶ | ❶ | ❶ | ||||
Clutch E[x] | ❶ | ❶ | ❶ | ❶ | ❶ | |||||
8HP 70 [y][z] |
700 N⋅m (516 lb⋅ft) 2008 |
48[9] 96 |
48[9] 96 |
69[10] 111 |
23[10] 85 |
2 3 |
7.0435 | 1.3216[j] | ||
Gear Ratio |
−3.2968[k] |
4.6957 |
3.1304[o] |
2.1039 |
1.6667[j][o][p] |
1.2845[o] |
1.0000 |
0.8392[o][p] |
0.6667 | |
Step | 0.7021[k] | 1.0000 | 1.5000 | 1.4879 | 1.2623[j] | 1.2975 | 1.2845 | 1.1917 | 1.2587 | |
Step 2[m] | 1.0081[o] | 1.1787 | 0.9729[o] | 1.0101[o] | 1.0779 | 0.9467[o] | ||||
Speed | –1.4243 | 1.0000 | 1.5000 | 2.2319 | 2.8174 | 3.6555 | 4.6957 | 5.5965 | 7.0435 | |
Δ Speed | 1.4243 | 1.0000 | 0.5000 | 0.7319 | 0.5855[p] | 0.8382 | 1.0401 | 0.9000[p] | 1.4478 | |
Ratio[aa] R & even |
||||||||||
Ratio[aa] odd |
||||||||||
| ||||||||||
Applications
[edit]Make | Model Years | Model | Final Drive Ratio |
---|---|---|---|
Cadillac | 2016–2019 | ATS | |
2016–2019 | CTS | ||
2020–present | CT4 | ||
2016–present | CT6 | ||
Chevrolet | 2016–2019 | Camaro | |
2017–present | Colorado | ||
GMC | 2017–present | Canyon |
Make | Model Years | Model | Final Drive Ratio |
---|---|---|---|
Cadillac | 2015–2017 | Escalade[11] | 3.23 |
2016–present | ATS-V | 2.85 | |
2016–present | CTS-V | 2.85 | |
2016–present | CT6 | 3.27 | |
Chevrolet | 2015–2019 | Corvette (C7) Stingray[12] | 2.41[a] or 2.73[b] |
2015–2019 | Corvette (C7) Z06[13] | 2.41 | |
2019 | Corvette (C7) ZR1 | 2.73 | |
2015–present | Silverado[14] | 3.23[a] or 3.42[c] | |
2015–present | Colorado | 3.42 | |
2016–2018 | Camaro SS | 2.77 | |
2017–present | Express[d] | ||
GMC | 2015–2017 | Yukon Denali · Denali XL | 3.23 |
2015–present | Sierra[14] | 3.23 | |
2015–present | Canyon | 3.42 | |
2017–present | Savana[d] | ||
Lawsuits
[edit]The 8L 90 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.[15]
See also
[edit]References
[edit]- ^ a b "USA Information Guide Model Year 2018" (PDF). Retrieved 15 July 2019.
- ^ "Cadillac Introduces New 8-Speed Automatic on CT6". Cadillac Media USA. Cadillac Media USA. 20 March 2015. Retrieved 20 March 2015.
- ^ "Timur Apakidze · Saturation Dive: The GM 8L 90 8-Speed Transmission". TTAC: The Truth About Cars. 23 April 2014. Retrieved 12 April 2024.
- ^ "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.
- ^ https://poweredsolutions.gm.com/products/8l45-8-speed-transmission/
- ^ https://poweredsolutions.gm.com/products/8l90-8-speed-transmission/
- ^ "Transmission Repair Cost Guide". Retrieved 15 July 2019.
- ^ "WIT · Whatever It Takes · Automatic Transmission Parts Catalog 2018+2019 Page 268". Retrieved 15 July 2019.
- ^ a b 8HP 70 Repair Manual · Picture 10106 p. 110 · Saarbruecken 2014 · https://avtgr.ru/upload/data/pdf/zf_instructions/8HP70.pdf
- ^ a b "Timur Apakidze · Saturation Dive: ZF 8-Speed Automatic". TTAC: The Truth About Cars. 11 March 2014. Retrieved 7 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.
- ^ a b "GM confirms 2015 Silverado, Sierra to get 8-speed automatic". Retrieved 18 June 2014.
- ^ "Class Action Lawsuit Filed Over Alleged Shifting Defect in Certain General Motors Transmissions". 19 December 2018. Retrieved 2 February 2019.