GM 8-speed automatic reliability: years to avoid, problems & recalls

By CarWhere Research · Updated November 7, 2026

GM's 8L90 and 8L45 eight-speed automatics in 2015–2019 Silverado, Sierra, Colorado, Canyon, Escalade, Yukon 6.2L, Camaro, Corvette, CTS, ATS and CT6 models are covered by GM service bulletins 16-NA-175 and 18-NA-355 for torque-converter clutch shudder at 25–80 mph. GM's prescribed fix is a full exchange to Mobil 1 Synthetic LV ATF HP. Vehicles built after the bulletin's early-2019 date breakpoints left the factory with that fluid.

GM 8-speed automatic at a glance

GM Hydra-Matic 8L90 and 8L45 eight-speed automatic: key facts
Fact	Detail
Type	Conventional automatic
Forward speeds	8
Built by	General Motors (Hydra-Matic)
Used by	Chevrolet, GMC, Cadillac
Years in use	2015–2019 model years in the vehicles covered here (later uses not covered)
Also known as	8L90, 8L45, M5U, M5T, M5N, M5X
Transmission-related NHTSA recalls listed	0
Warranty extensions / special coverage listed	0
Court settlements listed	1

What the GM 8-speed automatic is

The 8L90 and 8L45 are GM Hydra-Matic eight-speed automatics for rear- and four-wheel-drive vehicles. GM service bulletins list the 8L90 (RPO M5U/M5X) behind the 5.3L and 6.2L V8s in full-size trucks and SUVs, the Corvette and V-Series Cadillacs, and the 8L45 (RPO M5T/M5N) behind four-cylinder and V6 engines in the Colorado, Canyon, Camaro, ATS, CTS and CT6.

The best-documented issue is torque-converter clutch (TCC) shudder: a rumble-strip-like vibration at steady light throttle. GM first addressed it in bulletin 16-NA-175 (June 2016) with a triple fluid flush to new DEXRON HP fluid, then in bulletin 18-NA-355 (2019) with a full exchange to Mobil 1 Synthetic LV ATF HP. These transmissions are also the subject of a consumer class action in federal court in Michigan, where the Sixth Circuit vacated class certification in June 2025.

Which vehicles use the GM 8-speed automatic?

Makes, models and model years equipped with the GM 8-speed automatic
Make	Model	Model years	Notes
Chevrolet	Silverado (1500)	2015–2018	5.3L/6.2L V8 (L83, L86, L8B) with 8L90; fueleconomy.gov also lists 6-speed versions (4.3L and some 5.3L), so not every truck has the 8-speed[1][2]
GMC	Sierra (1500)	2015–2018	5.3L/6.2L V8 (L83, L86, L8B) with 8L90; like the Silverado, not every Sierra in these years has the 8-speed — check the RPO code[1]
Chevrolet	Colorado	2017–2019	3.6L V6 (LGZ) with 8L45 (RPO M5T); other Colorado engines used a 6-speed[1][3]
GMC	Canyon	2017–2019	3.6L V6 (LGZ) with 8L45 (RPO M5T)[1]
Cadillac	Escalade / Escalade ESV	2015–2017	6.2L V8 (L86) with 8L90; fueleconomy.gov lists both 6- and 8-speed versions for 2015 and only the 8-speed for 2016–2017[1][4]
GMC	Yukon / Yukon XL (6.2L)	2015–2017	6.2L V8 (L86) with 8L90[1]
Chevrolet	Camaro	2016–2019	2.0L turbo, 3.6L V6 and 6.2L V8 automatics (8L45/8L90); fueleconomy.gov lists the supercharged 6.2L automatic as a 10-speed from 2017[1][5]
Chevrolet	Corvette (C7)	2015–2019	6.2L LT1/LT4 automatic (8L90, RPO M5U); a 7-speed manual was also offered[1][6]
Cadillac	CTS	2016–2019	All automatic versions (8L45/8L90)[1][7]
Cadillac	ATS	2016–2019	Automatic versions (8L45/8L90)[1][8]
Cadillac	CT6	2016–2018	Engines with RPOs LGX, LGW and LTG (8L45/8L90)[1]

GM 8-speed automatic years to avoid vs. safer years

“Years to avoid” here means the model years with the most documented action — recalls, manufacturer warranty extensions or court settlements — not a prediction about any single vehicle. A car from these years with completed repairs and good records can be a sound buy; one without them deserves a closer look.

Model years with the most documented problems

2015–2018 Silverado and Sierra 1500 with the 8-speed (5.3L/6.2L) — Listed in GM bulletins 16-NA-175 and 18-NA-355 for torque-converter clutch shudder.[1][10]
2017–2019 Colorado and Canyon 3.6L (8L45) — Listed in GM bulletin 18-NA-355 for torque-converter clutch shudder.[1]
2015–2017 Escalade and Yukon 6.2L (8L90) — Listed in GM bulletins 16-NA-175 and 18-NA-355 for torque-converter clutch shudder.[1][9]

Later or safer years

8-speed vehicles built after the 18-NA-355 date breakpoints (Feb.–Mar. 2019) — GM's bulletin says vehicles built after those production dates are already equipped with the latest HP fluid.[1]

Known GM 8-speed automatic problems

Torque-converter clutch shudder at light throttle (2015–2019)

GM bulletin 18-NA-355 says customers may report a shake or shudder during light-throttle acceleration between 25 and 80 mph at steady speed, when the transmission is not shifting, and attributes it to torque converter clutch (TCC) shudder. The correction is a full fluid exchange to Mobil 1 Synthetic LV ATF HP; GM says intermixing other fluids or aftermarket additives will not give satisfactory results, and that the full effect can take up to 200 miles and at least two cold-to-hot drive cycles.[1]

Reported symptoms

Vibration like driving over rumble strips or rough expansion joints
Occurs at a steady 25–80 mph with light throttle, not during shifts

Earlier shudder fix: bulletin 16-NA-175 triple flush (2015–2019)

GM's first version of bulletin 16-NA-175 (June 2016) covered 2016 Escalade, Silverado, Sierra and Yukon models with the 5.3L or 6.2L and the 8L90, describing a 30–65 mph shudder and prescribing a triple fluid flush to new DEXRON HP fluid. By its February 2019 revision the bulletin covered 2015–2019 8-speed vehicles across Cadillac, Chevrolet and GMC, with a 25–80 mph range.[9][10]

Reported symptoms

Shake or shudder at steady light throttle
Feels like rough pavement or rumble strips

Class-action settlements involving the GM 8-speed automatic

Speerly et al. v. General Motors, LLC (originally filed as Francis et al. v. General Motors, LLC), No. 2:19-cv-11044[11][12][13][14]
U.S. District Court for the Eastern District of Michigan; appeal No. 23-1940, U.S. Court of Appeals for the Sixth Circuit
Vehicles: Model-year 2015–2019 GM vehicles with 8L45/8L90 transmissions, as defined in the class-certification order (Silverado, Sierra, Colorado, Canyon, Corvette, Camaro, Escalade, Yukon, CTS, CT6)
No settlement is reflected in these records. On Nov. 30, 2020 the district court granted GM's motion to dismiss in part and denied it in part. On Mar. 20, 2023 it certified 26 statewide subclasses. A Sixth Circuit panel affirmed certification on Aug. 28, 2024, but on June 27, 2025 the full (en banc) Sixth Circuit vacated the class-certification order and remanded the case to the district court.

Summaries describe the public settlement record only; settlements are not findings of fault.

NHTSA owner complaints: the power-train signal

Owners file complaints with NHTSA and tag each with the components involved. The tables below count, for each model year, how many complaints include NHTSA’s “power train” component (transmission, transfer case and driveline). Raw counts are not adjusted for sales volume or vehicle age, so compare the power-train share across years of the same model rather than across models.

Cadillac Escalade

In the model years that used the GM 8-speed automatic (highlighted), 40 of 186 NHTSA owner complaints (21.5%) list the power train as a component, versus 11% across the other Cadillac Escalade model years in the same snapshot. The highest count is the 2016 model year, with 21 power-train complaints.

Cadillac Escalade: NHTSA owner complaints by model year, all components vs. power train
Model year	All complaints	Power-train complaints	Power-train share
2008	167	7	4.2%
2009	58	4	6.9%
2010	43	2	4.7%
2011	65	2	3.1%
2012	26	1	3.8%
2013	17	4	23.5%
2014	19	1	5.3%
2015	102	26	25.5%
2016GM 8-speed automatic	101	21	20.8%
2017GM 8-speed automatic	85	19	22.4%
2018	21	3	14.3%
2019	24	1	4.2%
2020	13	2	15.4%
2021	74	8	10.8%
2022	71	11	15.5%
2023	119	15	12.6%
2024	41	7	17.1%
2025	14	2	14.3%

Chevrolet Corvette

In the model years that used the GM 8-speed automatic (highlighted), 43 of 620 NHTSA owner complaints (6.9%) list the power train as a component, versus 7.8% across the other Chevrolet Corvette model years in the same snapshot. The highest count is the 2015 model year, with 18 power-train complaints.

Chevrolet Corvette: NHTSA owner complaints by model year, all components vs. power train
Model year	All complaints	Power-train complaints	Power-train share
2008	587	32	5.5%
2009	152	7	4.6%
2010	84	4	4.8%
2011	84	11	13.1%
2012	56	2	3.6%
2013	82	3	3.7%
2014	61	9	14.8%
2015GM 8-speed automatic	64	18	28.1%
2016GM 8-speed automatic	103	12	11.7%
2017GM 8-speed automatic	255	2	0.8%
2018GM 8-speed automatic	51	1	2%
2019GM 8-speed automatic	147	10	6.8%
2020	34	6	17.6%
2021	11	7	63.6%
2022	20	5	25%
2023	22	6	27.3%
2024	20	2	10%
2025	10	1	10%

Cadillac CTS

In the model years that used the GM 8-speed automatic (highlighted), 24 of 75 NHTSA owner complaints (32%) list the power train as a component, versus 24.9% across the other Cadillac CTS model years in the same snapshot. The highest count is the 2016 model year, with 9 power-train complaints.

Cadillac CTS: NHTSA owner complaints by model year, all components vs. power train
Model year	All complaints	Power-train complaints	Power-train share
2008	175	21	12%
2009	167	28	16.8%
2011	108	25	23.1%
2012	67	4	6%
2013	72	13	18.1%
2014	144	84	58.3%
2015	47	19	40.4%
2016GM 8-speed automatic	31	9	29%
2017GM 8-speed automatic	26	9	34.6%
2018GM 8-speed automatic	8	3	37.5%
2019GM 8-speed automatic	10	3	30%

Cadillac ATS

In the model years that used the GM 8-speed automatic (highlighted), 22 of 90 NHTSA owner complaints (24.4%) list the power train as a component, versus 26.9% across the other Cadillac ATS model years in the same snapshot. The highest count is the 2016 model year, with 11 power-train complaints.

Cadillac ATS: NHTSA owner complaints by model year, all components vs. power train
Model year	All complaints	Power-train complaints	Power-train share
2013	160	45	28.1%
2014	102	28	27.5%
2015	28	5	17.9%
2016GM 8-speed automatic	35	11	31.4%
2017GM 8-speed automatic	32	5	15.6%
2018GM 8-speed automatic	21	6	28.6%
2019GM 8-speed automatic	2	0	0%

Source: NHTSA owner-complaint records (api.nhtsa.gov complaintsByVehicle), snapshot as of 2026-07-14. Complaints are unverified owner reports; one complaint can list several components.

Buying a used car with the GM 8-speed automatic: what to check

Confirm the transmission: many 2015–2018 Silverado and Sierra trucks used a 6-speed, so check the RPO label (M5U, M5X, M5T or M5N indicate an 8-speed).
Ask the dealer to check GM service history for the 18-NA-355 fluid exchange.
On a test drive, hold a steady 25–80 mph with light throttle on smooth pavement and feel for a rumble-strip vibration.
Ask whether any fluid service used Mobil 1 Synthetic LV ATF HP; GM says mixing in other fluids or additives defeats the fix.
Run the VIN through NHTSA's recall lookup for any open campaigns.

Related research

Year-by-year verdicts for models with the GM 8-speed automatic

Engines and model known-issues pages

Compare other transmissions

All transmissions: reliability and years to avoid

Frequently asked questions

Which GM vehicles have the 8L90 or 8L45 8-speed?

GM bulletin 18-NA-355 lists 2015–2018 Silverado and Sierra (5.3L/6.2L), 2017–2019 Colorado and Canyon 3.6L, 2015–2017 Escalade and Yukon 6.2L, 2016–2019 Camaro, 2015–2019 Corvette, 2016–2019 ATS and CTS, and 2016–2018 CT6. Not every truck in those years has the 8-speed, so check the RPO code.

What causes GM 8-speed shudder?

GM bulletin 18-NA-355 attributes the 25–80 mph light-throttle shudder to torque converter clutch shudder. The bulletin's fix is a full transmission fluid exchange to Mobil 1 Synthetic LV ATF HP, using GM's specified exchange procedure rather than a simple drain and fill.

Is there a recall for GM 8-speed shudder?

No. GM handled the shudder through service bulletins 16-NA-175 and 18-NA-355, not a safety recall. The 18-NA-355 warranty section refers to repairs under the vehicle's powertrain coverage, so whether the fluid exchange is free depends on the vehicle's warranty status.

Will a regular transmission fluid change fix the shudder?

GM's bulletin says the exchange must be done as published to get enough new HP fluid into the system, and that mixing other fluids or aftermarket additives will not give satisfactory results. GM also says the full effect can take up to 200 miles and two cold-to-hot drive cycles.

What happened in the GM 8-speed class action?

In Speerly v. General Motors (E.D. Mich., No. 2:19-cv-11044), the district court certified 26 statewide subclasses in March 2023. A Sixth Circuit panel affirmed in 2024, but the full Sixth Circuit vacated certification on June 27, 2025 and sent the case back to the district court.

How CarWhere compiled this page

Every problem, recall, warranty extension and settlement above is CarWhere’s own summary of a primary record — NHTSA recall campaigns, manufacturer service bulletins and warranty-extension notices filed with NHTSA, manufacturer press material, and court or settlement-administrator records — and is numbered to its source below. We list a model year under “years to avoid” only when a manufacturer, regulator or court record ties it to the transmission. Complaint counts come from NHTSA’s public owner-complaint data, counted once per complaint. We do not estimate failure rates or repair costs. See also the years-to-avoid methodology.

Sources

Descriptions are CarWhere’s own summaries of the records below. Recall details are as reported to NHTSA by the manufacturer.

GM Service Bulletin 18-NA-355 (Aug. 2019): Shake and/or shudder during light throttle acceleration between 25 and 80 mph (8L45/8L90) — General Motors (via NHTSA)
2017 Chevrolet Silverado C15 2WD — transmission options — fueleconomy.gov (U.S. DOE/EPA)
2018 Chevrolet Colorado 2WD — transmission options — fueleconomy.gov (U.S. DOE/EPA)
2016 Cadillac Escalade 2WD — transmission options — fueleconomy.gov (U.S. DOE/EPA)
2018 Chevrolet Camaro — transmission options — fueleconomy.gov (U.S. DOE/EPA)
2017 Chevrolet Corvette — transmission options — fueleconomy.gov (U.S. DOE/EPA)
2017 Cadillac CTS — transmission options — fueleconomy.gov (U.S. DOE/EPA)
2017 Cadillac ATS — transmission options — fueleconomy.gov (U.S. DOE/EPA)
GM Service Bulletin 16-NA-175 (June 2016): Shake and/or shudder during light throttle acceleration, 30–65 mph (8L90) — General Motors (via NHTSA)
GM Service Bulletin 16-NA-175 (Feb. 2019 revision): Shake and/or shudder, 25–80 mph (8-speed automatic) — General Motors (via NHTSA)
Francis et al. v. General Motors, LLC, No. 19-11044 — Opinion and order on motion to dismiss (ECF No. 92, Nov. 30, 2020) — U.S. District Court for the Eastern District of Michigan (via GovInfo)
Speerly et al. v. General Motors, LLC, No. 19-11044 — Order certifying 26 statewide subclasses (ECF No. 284, Mar. 20, 2023) — U.S. District Court for the Eastern District of Michigan (via GovInfo)
Speerly v. General Motors, LLC, No. 23-1940 (6th Cir. Aug. 28, 2024) — panel opinion — U.S. Court of Appeals for the Sixth Circuit (via GovInfo)
Speerly v. General Motors, LLC, No. 23-1940 (6th Cir. June 27, 2025) (en banc) — U.S. Court of Appeals for the Sixth Circuit (via GovInfo)

Independent reference compiled by CarWhere Research — not affiliated with or endorsed by any manufacturer or transmission supplier. Product and model names are trademarks of their owners.