GMC Terrain Transmission Problems & Cost | 6T40 | 6T70

The compact GMC Terrain was one of the first true American luxury crossovers, and came equipped with the 6-speed 6T40 transmission and the 6T70 transmission. But they aren’t without their problems though, so let’s look at some of the most common GMC Terrain transmission problems, look at cost estimates and figure out what you can do about them.

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?

GMC Terrain Transmission Models

GMC Terrain: 6T70 Transmission
GMC Terrain: 6T40 Transmission

GMC Terrain Transmission Replacement Cost Estimate

Pricing varies by model. To be 100% sure on pricing, have your VIN# handy and use our Get An Estimate feature to look up your transmission by VIN#.

Replacement GMC Terrain Transmission Prices:

What are the DTC codes related to GMC Terrain transmission problems?

GMC Terrain Transmission Recalls

None Found

GMC Terrain Technical Service Bulletins (TSB)

TSB PI0324F – No forward, no reverse, engine will not crank, engine will not start – 6T30 Transmission | 6T40 Transmission | 6T45 Transmission | 6T50 Transmission
2011-2014 Buick LaCrosse – 2011-2014 Buick Regal – 2012-2014 Buick Verano – 2013-2014 Buick Encore – 2011-2013 Chevrolet Malibu – 2011-2014 Chevrolet Cruze – 2011-2014 Chevrolet Equinox – 2012-2014 Chevrolet Captiva Sport – 2012-2014 Chevrolet Orlando – 2012-2014 Chevrolet Sonic – 2013 Chevrolet Malibu Eco – 2013-2014 Chevrolet Trax – 2011-2014 GMC Terrain
Problem – Some of the symptoms of this problem include; the transmission will not engage, the engine cranks but will not start, transmission fluid leaks, unusually harsh shifts, transmission slipping, certain transmission gears will not engage. These diagnostic trouble codes may also be present; P0776, P0796, P2714, P2723.
Solution – These problems may be caused by low line pressure due to a damaged transmission pump.

TSB PI0376A – Flare or slipping on the 2-6 shift – 6T40 Transmission | 6T45 Transmission
2011 Buick LaCrosse – 2011 Buick Regal – 2011 Chevrolet Cruze – 2011 Chevrolet Equinox – 2011 Chevrolet Malibu – 2011 GMC Terrain (equipped with 4 Cylinder Engine and 6T40 or 6T45)
Problem – When this common 6T40/6T45 transmission problem occurs, the driver may experience slipping and/or a sudden flare/surge when the transmission shifts into or out of 2nd/6th gear.
Solution – This problem is often caused by debris blocking the opening on the channel plate and spacer plate that provides oil to the 2-6 clutch regulator valve. To correct the issue, the channel plate, spacer plate and valve body will have to be cleaned.

TSB 13120A – Torque converter clutch sticking – 6T70 Transmission | 6T75 Transmission
2013 Buick Enclave – 2013 Cadillac SRX – 2013 Cadillac XTS – 2013 Chevrolet Malibu – 2013 Chevrolet Traverse – 2013 GMC Acadia – 2013 GMC Terrain
Problem – The torque converter clutch solenoid can stick due to debris in the transmission. When the vehicle is at the end of a coast-down, as the vehicle is coming to a stop, a stuck solenoid will fail to release the torque converter clutch. This keeps the engine directly connected to the driven wheels. As the vehicle stops, the engine speed will be pulled down below normal idle speed and the engine may stall. The vehicle can be immediately restarted and driven.
Solution – The valve control solenoid should be replaced, and the transmission control module will have to be reprogrammed in order to correct the problem.

Common GMC Terrain Transmission Problems

Input/Output Speed Sensor Issues – 6T70E Transmission
Problem – When repairing a failed input speed sensor or output speed sensor, steering system damage could occur.
Solution – To avoid damage to the clock springs, the splined steering knuckle must be prevented from falling out of the steering rack when dropping the subframe to access the valve body.

Lack of Response
Leaking Fluid
Low Fluid
Burning Smell
Grinding or Shaking
Whining, Clunking or Humming
Refuses to Go Into Gear
Torque Converter Issues
Valve Body Issues
Transmission Noisy in Neutral
Gears Slipping
No 3rd or 4th Gear
No 1st or 2nd Gear
No Reverse
Dragging Clutch
Trouble Codes / Check Engine Light

Can I drive with a transmission problem?

If your GMC Terrain can still make it up and down the road, you might say “It’s fine, I’ll just drive it until I can get it fixed”. But that is not always a good idea, depending on the symptoms. You see, there are a lot of (very expensive) moving parts inside of a transmission, and if something isn’t right, continuing to drive with a transmission problem could damage something else.

How often does a GMC Terrain transmission need to be replaced?

The overall lifespan of a GMC Terrain transmission largely depends on how well it was maintained. Factory design flaws also factor into this equation, along with how/how hard you drive. But on average, we’ve seen the GMC Terrain transmission last for between 130,000-180,000 miles. A high quality replacement transmission however, can last considerably longer if all of the factory design flaws have been addressed and the vehicle has been maintained.

How are GMC Terrain transmission issues diagnosed?

It is fairly easy to guesstimate what the root cause of your GMC Terrain transmission problems might be, but you won’t truly know unless you have the right tools and experience. A good mechanic or transmission repair center will be able to connect your truck to a computer and find out which diagnostic trouble codes (DTC’s) have been stored. Once they know what to look for, they can perform a visual inspection to verify the problem.

How is a GMC Terrain transmission replaced?

In order to replace your GMC Terrain transmission, the truck has to be lifted from the ground in order to gain access to all of the parts that will need to be unbolted. Then the transmission can be lowered to the ground (typically with a transmission jack), so the new transmission can be installed. Once it is in place, for the 6L80, the vehicle PCM will have to be reprogrammed / reflashed to accept the new transmission using the latest GM subscription.

Recommendations for GMC Terrain transmission issues?

To save time and get back on the road faster, have your 17-digit truck VIN# handy and you can get an online quote for a reman GMC Terrain transmission here, then find a local shop using our Find a Shop guide to install it for you.

How to Solve GMC Terrain Transmission Problems

Solution A: Buy a Used GMC Terrain Transmission

The quickest way to fix your transmission problems is to simply buy a used transmission or used transmission. These can be found at most junk yards, and they often come with a 30-90 day warranty. However, there’s no way to determine the actual condition of the internal components, so you could be spending a bunch of money to have the exact same problems. Plus, that warranty only covers the transmission if it’s defective, not the labor costs that you’ll have to pay.

Solution B: Buy a Rebuilt GMC Terrain Transmission

Another option would be a rebuilt transmission or rebuilt transmission. A local repair shop will remove your transmission, then install a bunch of new parts during the rebuild. The problem here is, the skills and experience of each transmission rebuilder will vary widely from shop to shop, so you could have problems from something that wasn’t adjusted properly. And the 1-2 year warranty might only cover you at certain transmission repair shops, in a specific geographical area.

Solution C: Buy a Remanufactured GMC Terrain Transmission

Many owners depend on their vehicle to commute and get things done. Their gasoline engines are designed to go 100’s of thousands of miles, so it makes sense to invest in a remanufactured transmission.

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?

What Problem Does Your GMC Terrain Have?

Let us know the year, mileage and problem you’re having as well as any trouble (OBD) codes you’ve found. If you’ve been given a quote or paid for a repair, we’d like to hear about that too!