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In the mid-2000s Ford and GM worked together on front-drive six-speed automatics. The larger pair became the GM 6T70/6T75 and Ford 6F50/6F55. The smaller units, the GM 6T40/6T45 and Ford 6F35, landed in the compact and midsize cars and crossovers both companies were selling by the millions.
Customers and even some parts counters assume the 6F35 and 6T40 are the same box with different badges. They share the general idea: a compact clutch-to-clutch six-speed with a 1-2-3-4 clutch, 3-5-reverse clutch, 2-6 clutch, low-reverse clutch and a one-way clutch in first. But each company engineered and built its own unit with its own case, valve body, controls and calibration. Treat them as cousins, not twins.
Who Got Which
| Unit | Common Vehicles |
|---|---|
| Ford 6F35 | Fusion, Milan, MKZ (2.5 and EcoBoost four-cylinders), Escape and Mariner 2009 and up, Transit Connect, some Mazda Tribute |
| GM 6T40 | Chevy Cruze, Sonic, Malibu (four-cylinder), Equinox and Terrain 2.4, Buick Verano, Encore, Trax |
| GM 6T45 | Higher-torque version: Equinox/Terrain, Captiva, Malibu, Regal and others with larger fours or the 3.0/3.6 in some years |
GM also built a 6T30 for the smallest cars and a 6T50 in some later applications. The 6T40 and 6T45 share most of their architecture, which is why so many GM parts are listed "6T40/6T45."
Key Differences
| Feature | Ford 6F35 | GM 6T40 / 6T45 |
|---|---|---|
| Built by | Ford | GM |
| Controls | Valve body with integrated solenoid body; separate PCM/TCM depending on year | Valve body with a TEHCM (control solenoid valve and TCM combined) on the valve body [2] |
| Generations | Gen 1 from 2009 to mid-2013; Gen 2 from 2013 (and later Gen 3) with new solenoid dampers, solenoids and valve body casting [1] | Several running changes, notably 3-5-R wave plate updates |
| Signature failure | Solenoid body faults, harsh or erratic shifts, 3-5-R and low-reverse clutch wear | Broken 3-5-R wave plate causing no 3rd, 5th or reverse |
| Parts interchange with the other | None of the major hard parts | None of the major hard parts |
Common Problems
Ford 6F35
- Harsh or erratic shifts: slams into 2nd or 3rd, delayed engagement, or a flare on the 3-4. Ford released several software updates; always check for a reflash first.
- Solenoid body faults: shift solenoid and line pressure codes, often with the transmission going into a fail-safe gear. The solenoid body can be replaced without pulling the transmission. Gen 2 and Gen 3 solenoids are not interchangeable with Gen 1 or with 6R60/6R80 solenoids, so order by generation [1].
- TCC slip from the stator bushing: Sonnax says the OE stator support bushing wears early on both the 6F35 and the 6T40, causing TCC slip, no TCC and codes P0741 and P1744. On the 6F35 the stator bore is tapered from the factory, so the bore must be machined before a new bushing is pressed in [5].
- Clutch wear from heat: slipping in 3rd, 5th or reverse points to the 3-5-R clutch; no reverse or a bind in first can point to the low-reverse clutch or one-way clutch.
- Escape and Fusion overheating: small fluid capacity and a hard-working four-cylinder in stop-and-go traffic cook fluid. Many of these units were never serviced.
GM 6T40 / 6T45
- 3-5-R wave plate break: the classic. GM bulletin PI0780A lists slip or no reverse, slip or no 3rd and DTC P0776 from a broken 3-5-R apply (waved) plate, and recommends a new 3-5-R piston and waved plate any time the unit is apart. GM also says the debris must be cleaned out with the case halves separated, and the pump filter and control solenoid filter plate replaced [3]. Sonnax notes the plate most often broke on 2007-2009 units, that GM later shot-peened the plate, and that updated plates still fail and can damage the drum splines [4].
- TEHCM faults: erratic shifts, no communication or solenoid codes. The unit must be programmed after replacement.
- Harsh 1-2 or 2-3 shifts: often adaptation or fluid related, but they also show up when the 2-6 clutch is wearing.
- Leaks: axle seals and the side cover are common seep points on older Cruzes and Equinoxes.
How to Tell Which You Have
On the road this is easy: a Ford product has a 6F35, a GM product has a 6T30, 6T40, 6T45 or 6T50. The hard part is the GM side. GM RPO codes on the glovebox or door sticker narrow it down: GM bulletin PI0780A lists RPO MHC, MHJ, MH7, MH8 and MH9 across the 6T30/40/45/50 family [3], so decode the RPO against the VIN when ordering, because usage varies by model and year. On the Ford side, read position 8 of the door tag (6 = 6F35) and know the model year, because Gen 1 and Gen 2 6F35 parts are not interchangeable [1].
What Repairs Cost
| Job | Parts Only (DIY) | Typical Shop Price |
|---|---|---|
| Fluid drain and fill | $40-$80 | $150-$250 |
| 6F35 solenoid body | $250-$500 | $600-$1,100 |
| 6T40 TEHCM / control module | $300-$600 | $700-$1,200 with programming |
| 6T40 wave plate repair (internal) | $150-$400 parts | $1,800-$2,800 |
| Full rebuild, either unit | $250-$700 kit plus hard parts | $2,500-$3,800 |
Fluid: 6F35 takes Mercon LV per Ford's Motorcraft fluid chart [6]. 6T40/6T45 takes Dexron VI or newer Dexron ULV depending on year. Both are low-capacity transmissions where a quart low matters, and both should be checked at operating temperature using the factory procedure.
Repair or Replace
These are often in cars worth less than a shop rebuild. If the problem is electrical (solenoid body or TEHCM) and the fluid is not burnt, fix the controls and service the fluid. If the 6T40 lost reverse from a wave plate, a rebuild with the updated plate is the right call because pieces travel. If a 6F35 is slipping in multiple gears with burnt fluid and metal in the pan, a rebuild or a reman unit makes more sense than throwing a solenoid body at it.
Shop-Floor Verdict
Neither one is a bad transmission when the fluid is changed every 50,000 to 60,000 miles. The 6T40 has one well-known mechanical weak point with a known fix. The 6F35 is more of a control and heat problem. If you are diagnosing either, start with fluid level and condition, scan for codes and software updates, and only then condemn hard parts.
6F35 and 6T40 Parts
Master rebuild kits, solenoid sets and filter kits for Ford 6F35 and GM 6T40/6T45 transmissions.
6T40 Rebuild Kit → 6F35 Rebuild Kit → 6F35 Valve Body → Browse CoreTransmissionParts.com →FAQ
Is the Ford 6F35 the same as the GM 6T40?
No. They come from the same period of Ford-GM six-speed cooperation and share a general layout, but each company built its own case, valve body and controls. Major parts do not interchange.
What is the most common 6T40 failure?
A broken 3-5-reverse wave plate, which causes loss of 3rd, 5th and reverse.
What fluid does the 6F35 use?
Ford Mercon LV.
Can a 6F35 solenoid body be replaced without removing the transmission?
Yes. The valve body and solenoid body are accessible after removing the side cover, though it is a tight job in some vehicles.