GM 6T40 and 6T45 Buyer's Guide: Cruze, Malibu, Equinox

If your Cruze, Malibu or Equinox just lost Reverse, the transmission is almost certainly a GM 6T40 or its heavier twin, the 6T45. And the part that failed is very often one thin steel ring inside it.

GM launched the family in the 2008 Chevrolet Malibu. Inside GM it was the "global six-speed," and it went into more front-drive cars than any other GM six-speed of its time.

The 6T40 went into the smaller engines:

• Chevrolet Malibu (2008–2016, four-cylinder)
• Chevrolet Cruze (2011–2016 in the US)
• Chevrolet Impala (2014–2019, four-cylinder)
• Chevrolet Trax and Buick Encore (2013 on)
• Buick Verano, Regal and LaCrosse (roughly 2011–2017, depending on engine)

The 6T45 is the heavy-duty version, and it's what you'll find behind the 2.4 in the 2010–2017 Equinox and GMC Terrain. The two look alike. The 6T45 runs a wider drive chain (1.25 inches against the 6T40's 1 inch), a five-pinion input planetary, a heavier case and a heavier differential. They don't swap for each other, and front-drive and all-wheel-drive versions carry different codes on top of that. We match yours by VIN.

What you notice first varies. A transmission-parts maker that sells a repair kit for exactly this failure lists the symptoms: code P0776, flared or harsh shifts, a hard 2–3 or 4–5, no 3rd, no 5th, and a harsh or missing Reverse. Some cars go from fine to nothing in a single drive.

Here's the part that matters when you're buying: a rebuild with an updated factory plate can still fail the same way. That same maker says so in its own tech notes, and its kit replaces the toothed plate with a tooth-free design. Ask whoever supplies your unit what's in the 3-5-Reverse pack. A good answer names the part.

Like the rear-drive 6L80, the 6T40 carries its control module on the valve body. GM calls it the control solenoid valve assembly, and shops call it the TEHCM. It bundles the module, the solenoids, pressure switches and the fluid temperature sensor.

So a replacement transmission, or a replacement TEHCM, needs programming to your VIN, and then an adaptive relearn. Skip that and a fresh unit shifts like a worn one.

Dexron VI, and nothing else. Most of these have no dipstick, so the level is set at a check plug on the case, with the engine running and the fluid at the temperature GM's procedure specifies.

That procedure matters more here than on most transmissions. The ATRA seminar notes on this family warn that as little as half a quart too much can push fluid out of the vent. A quick "top-off" at a lube shop is how a lot of 6T40s end up wet on the outside and low a month later.

The drain plug only empties about half of the fluid, too. A real fluid change drops the pan.

If the car died and you're arranging the tow, the rule from the same notes: don't tow a 6T40 car with the rear wheels up and the front wheels on the ground. An AWD model shouldn't be dolly-towed either. A flatbed is the safe answer for all of them.

• **Programming and relearn,** written down.
• **The cooler.** A 6T40 that broke its wave plate has sent steel through the fluid. The cooler is machine-flushed and flow-tested, or replaced, and the invoice says which.
• **Fluid type and quantity.** Dexron VI, and how much went in.
• **The converter, installed vertically.** The converter has a lip seal that the factory manual says is damaged if it goes on at an angle. Your installer will know. It's still worth a sentence when you drop the car off.

Expedia Protection covers personal-use units for 5 years with unlimited miles. A Malibu or Cruze doing rideshare or fleet work falls under the manufacturer's commercial term instead, typically 18 months or 75,000 miles. And before anyone pulls a unit over a warranty concern, get a written pre-authorization number from us.

If you're comparing a used unit against a remanufactured one, the question is simple: has anyone opened the 3-5-Reverse pack? On a used 6T40 from a salvage car, nobody has. [Our reman-vs-used comparison](/blog/reman-vs-used-engines-transmissions-how-to-choose) covers the rest of the tradeoff, and [the break-in guide](/blog/transmission-break-in-first-500-miles) covers the first 500 miles.

• Warranty policy and Expedia Protection: /warranty
• Pre-authorization before removing the unit: /blog/pre-authorization-before-removing-unit
• When your transmission needs a reflash: /blog/when-transmission-needs-reflash
• Valve body issue or software issue: /blog/valve-body-issue-or-software-issue
• Lifter tick after engine replacement: /blog/lifter-tick-after-engine-replacement