NHTSA ID Number: 10219391
Manufacturer Communication Number: 21-NA-181
Summary
This service bulletin provides 9th gear operation information to respond to customers that may comment on transmission shift operation.
Condition
Some customers may comment that the transmission doesn’t shift into 9th gear or
maintain 9th gear operation to customer expectations.
Information
The GM 9-speed transmission does use all 9 gears when most efficient to do so. The vehicle’s control system senses the operating conditions and chooses the correct gear to deliver optimum performance and fuel economy. The control calibration is also tailored for each vehicle application and engine type. On the highway for example, optimal fuel economy may actually be achieved in 8th gear rather than 9th gear depending on a number of factors including vehicle speed, engine load, and throttle input. 9th gear is engaged when appropriate.
Note: Replacing transmission components or complete assemblies will not change the condition. To ensure 9th gear is operating, verify 9th gear is not being commanded on a test drive. Then with GDS2, manually command 9th gear. If achieved, the vehicle system is operating correctly.
32 Affected Products
Vehicles
| MAKE | MODEL | YEAR |
BUICK | ENCORE GX | 2020-2022 |
| BUICK | ENVISION | 2021-2022 |
| CADILLAC | XT4 | 2019-2022 |
| CADILLAC | XT5 | 2020-2023 |
| CADILLAC | XT6 | 2020-2023 |
| CHEVROLET | BLAZER | 2020-2023 |
| CHEVROLET | TRAILBLAZER | 2021-2022 |
| GMC | ACADIA | 2020-2023 |
| GMC | TERRAIN | 2018-2022 |
1 Associated Document
Manufacturer Communications
Bulletin No.: 21-NA-181
Date: September, 2022
- Meets and exceeds DEXRON ULV & MERCON ULV Specs -Formulated to meet OEM specifications for modern Ford and GM 10-speed transmissions requiring ultra-low viscosity ATF like DEXRON ULV and MERCON ULV.
- Enhanced with FR3 Friction Reducer - Features our proprietary FR3 for smoother gear shifts, reduced wear, and improved thermal stability—delivering superior transmission performance.
- Professional Grade, DIY Ready - Perfect for shops and advanced DIYers. Compatible with most ATF fluid exchange systems and transmission service kits. Always consult your vehicle's manual for correct specification.
- Maximum Performance - GREEN DIAMOND ULV ATF also provides increased oxidation and thermal stability, deposit and sludge prevention, reduced breakdown, longer drain intervals and higher wear resistance than our competitors.
- Compatible With Ford & GM 10-Speed Vehicles - Designed for use in vehicles requiring ULV ATF including Ford F-150, Expedition, and GM Silverado, Sierra, Tahoe with 10L80, 10R80, or 10-speed automatic transmissions.
- Widely compatible with a huge range of vehicles and specifications including: Dexron ULV, Mercon ULV, Nissan Matic P, JATCO 9 Speed, BMW 83-22-2-413-477 ATF 7 and many other ULV applications.
- EXTENDED DRAIN: Long drain intervals of up to 150,000 miles for standard driving and 70,000 miles for heavy-duty applications
- COLD WEATHER READY: Engineered for extreme conditions with a pour point down to -50°F, ensuring top fuel economy and performance in freezing temperatures
- OEM REPLACEMENT: 100% synthetic ATF Compatible with Mercon ULV, Dexron ULV, WSS-M2C949-A or MB 2236.17, and other ULV applications in European and US cars, trucks, and SUVs
- ADVANCED COMPATIBILITY: Compatible with GM 10L80/10L90, Escalade (2021+ with 10L80), CT6 3.0TT and 4.2TT (2019+ with 10L80), Silverado 1500 (2019+ with 10L80), Camaro SS / ZL1 (2017+ with 10L80/90), Tahoe and Suburban (2021+ with 10-speed), Sierra 1500 (2019+ with 10L80), and Yukon and Yukon XL with 10 speed transmissions
- Helps enhance transmission cooling function
- Designed to protect metal surfaces from wea
- Formulated to condition gaskets
- Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional
- ACDelco GM Original Equipment parts are designed, engineered and tested to rigorous standards, and are backed by General Motors.
- Formulated with premium synthetic base oils to achieve low viscosity and minimize deposits
- Provides excellent thermal and oxidation performance
- Durable friction modifiers help prevent shudder
- Advanced anti-wear technology to better prevent gear wear
Last update on 2026-05-27 / Affiliate links / Images from Amazon Product Advertising API
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Copyright 2022 General Motors LLC. All Rights Reserved. Service Bulletin Bulletin No.: 21-NA-181 Date: September, 2022 INFORMATION Subject: Information on 9TH Gear Operation Brand: Model: Model Year: VIN: Engine: Transmission: (9-Speed from to from to Automatic) Buick Encore GX 2020 2023 — — L3T M3F Envision 2021 LSY M3G, M3H Cadillac XT4 2019 LSY M3H XT5 2020 LSY M3G XT6 Chevrolet Blazer 2020 LSY M3T Trailblazer 2021 L3T M3F GMC Acadia 2020 LSY M3G Terrain 2018 LYX M3U Involved Region or Country North America, Europe, Middle East, Israel, Cadillac Korea (South Korea), China Condition Some customers may comment that the transmission doesn’t shift into 9th gear or maintain 9th gear operation to customer expectations. Information The GM 9-speed transmission does use all 9 gears when most efficient to do so. The vehicle’s control system senses the operating conditions and chooses the correct gear to deliver optimum performance and fuel economy. The control calibration is also tailored for each vehicle application and engine type. On the highway for example, optimal fuel economy may actually be achieved in 8th gear rather than 9th gear depending on a number of factors including vehicle speed, engine load, and throttle input. 9th gear is engaged when appropriate. Note: Replacing transmission components or complete assemblies will not change the condition. To ensure 9th gear is operating, verify 9th gear is not being commanded on a test drive. Then with GDS2, manually command 9th gear. If achieved, the vehicle system is operating correctly. Parts Information No parts are required for this repair. Warranty Information For vehicles repaired under the Powertrain coverage, use the following labor operation. Reference the Applicable Warranties section of Investigate Vehicle History (IVH) for coverage information. Labor Operation Description Labor Time 8486038* Confirm 9TH Gear Operation 0.3 hr *This is a unique Labor Operation for bulletin use only. Page 2 September, 2022 Bulletin No.: 21-NA-181 Version 4 Modified Released August 12, 2021 Revised December 21, 2021 – Added RPO M3H to Envision. Revised April 08, 2022 – Add 2022 Model Year to Terrain. Revised August 29, 2022 – Add 2023 Model Year. GM bulletins are intended for use by professional technicians, NOT a “do-it-yourselfer”. They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information. WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
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