Transmission History by Year - GMC Terrain
2010 - 2017: 6-speed automatic (6T40 on 2.4L; 6T45 on 3.0L V6 AWD). 2018 - 2024: 9-speed automatic (9T50) on 1.5T and 2.0T engines. AWD models use electronic on-demand rear coupling.
Expert GMC Terrain transmission service in Chicago. Free computer diagnostic, 2-year / 24,000-mile warranty on rebuilds, all years.
We will contact you as soon as a service member is available by call, text, or email.
2010 - 2017: 6-speed automatic (6T40 on 2.4L; 6T45 on 3.0L V6 AWD). 2018 - 2024: 9-speed automatic (9T50) on 1.5T and 2.0T engines. AWD models use electronic on-demand rear coupling.
The 6T40/6T45 in Terrain is a compact transaxle with the same solenoid failure pattern as Equinox and Malibu. Solenoid replacement without a full rebuild is possible when valve body is otherwise sound. The 9T50 in newer Terrain requires TCM software update before mechanical diagnosis.
6T40/6T45 uses Dexron VI. 9T50 uses Dexron HP. Change every 45,000 miles.
Verify exact spec on the dipstick label or owner's manual before fill. Recommended change interval: every 60,000 miles for normal driving, 30,000 miles under severe service (towing, stop-and-go, hot climates). Pan service typically takes 6 - 8 quarts; a full fluid exchange takes 10 - 14 quarts depending on cooler-line capacity.
Solenoid: 1 - 2 days. 6T40/6T45 rebuild: 2 - 3 days. 9T50 rebuild: 3 - 4 days.
Fluid service and inspection complete the same day. Solenoid or sensor replacement: 1 day. Torque converter or seal repair: 2 - 3 days. Full rebuild with road test: 4 - 6 days. Time estimates assume parts in stock - call (312) 626-8759 to verify availability for your specific vehicle.
Every vehicle needs diagnosis before anyone can promise a repair path. These are the situations we help organize before you decide what to do next.
Tell us when it happens, whether reverse still works, and if warning lights are on. A scan and fluid check come before guessing at a rebuild.
Fluid condition, leak location, and driving distance matter. If the vehicle is slipping badly or overheating, towing may be the safer next step.
A failed solenoid, valve body, converter, or internal clutch problem can lead to very different repair paths. The goal is a clear diagnosis and written estimate.
P0750 on 6T40/6T45 is solenoid A failure. Often repairable without a rebuild ($400 - 650). Get a free diagnostic.
The 9T50 nine-speed has known shift quality issues - a TCM software update often resolves hunting. Try that first.
2 - 3 business days.
Yes - the Terrain and Equinox share transmissions across the same generation (6T40/6T45 for Gen1, 9T50 for Gen2). Same parts, same procedures.
TCC shudder on 6T40 - common on 2.4L Terrain. Dexron VI fluid exchange is the first step ($149). If it persists, torque converter inspection.
Same-day appointments available. Honest estimates, no surprises. We've been doing this since 1987.
