6T70 Equinox Common Problems and Fixes

The Equinox is one of the most common 6T70 vehicles we see, and also one of the most commonly misidentified. Plenty of Equinoxes never had a 6T70 at all, and the ones that did span both generations of the unit, which matters more on this transmission than almost any other GM six-speed. This guide sorts the Equinox 6T70 problems by build, with the bulletin numbers, codes, specs and part numbers behind each one. Numbers in brackets point to the Sources list at the bottom.

First: does this Equinox even have a 6T70?

Only the V6 cars do. GM's wave plate bulletin and special coverage list the 2008-2009 Equinox with the 6T70/75 under RPO MH2 (FWD) or MH4 (AWD) [1][2]. GM bulletin 18-NA-358 lists the 2014-2017 Equinox with the 6T70 under RPO M7U or M7W [3]. Four-cylinder Equinoxes use the smaller 6T40/45 family, which looks similar on a parts screen and shares almost nothing internally. The 2018 and later Equinox dropped the V6, and the 6T70 left with it. Pull the RPO label in the glovebox before you order anything.

The second question is generation. ATRA's product-issues seminar explains that the 6T70 under RPO M7W or M7U got a major controls update for 2013, while units with other RPO codes did not get it until 2014 production, so Gen 1 and Gen 2 units were both built in 2013 [4]. Transmission Digest says Gen 2 components were used selectively from the start of 2013 and all 2014 and later units should be Gen 2 [6]. In Equinox terms, plan on 2008-2012 being Gen 1 and 2014-2017 being Gen 2, and verify a 2013 by the unit, not the calendar.

Recommended 6T70 parts

What fixes the Equinox patterns below: a Gen 1 kit with pistons for a 2008-2012 unit that lost its 3-5-R clutch, a Gen 2 kit for 2013-later builds (Gen 2 pistons and frictions are not interchangeable with Gen 1), and a valve body for the 2014-2017 shudder and flare covered by GM bulletin 18-NA-358.

6T70 Gen 1 Master Rebuild Kit with Pistons 2007-2012

$367.99

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6T70 Transmission Master Rebuild Kit Gen 2 2013-Up

$447.99

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6T70 Valve Body 2014

$216.98

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1. No reverse, no 3rd, no 5th: the 3-5-R wave plate

This is the failure the early 6T70 is known for, and the 2008-2009 Equinox is on the list. GM bulletin 09-07-30-012F describes a check engine light, no reverse, and a slip, flare or harsh shift in 3rd and/or 5th, usually with P0776 (Clutch Pressure Control Solenoid 2 Stuck Off). The debris can also set P0777, P2723, P0717, P0716, P2715 and P2714 on their own [1]. The cause is a broken 3-5-R clutch wave plate that lets the apply piston over-stroke, so the piston leaks and loses apply. GM says it normally does not happen before about 20,000 miles [1].

GM backed it with special coverage 14404B: 2008-2009 Equinox (along with Malibu, Torrent, Vue, Acadia, Enclave, Outlook, Aura, G6 and the 2009 Traverse) got 10 years or 120,000 miles from the in-service date [2]. Every one of those trucks is past the ten-year mark now, so the job lands on independent shops at full price.

Confirming it

ATRA's advice is to keep it simple: unplug the transmission and see whether reverse is being blocked electrically. If reverse engages unplugged, the input sun shell (a separate early failure with welds that break) is not your problem, and the 3-5-R clutch is [4]. A pan with steel fragments on the magnet tells you the rest. Do not condemn the control solenoid body on the P0776 alone. The bulletin says the TEHCM should not be replaced for any DTC unless the service information diagnostics say so [1].

The repair, done right

GM released updated waved plate 24254103 and recommends installing it any time the transmission is apart for any reason [1]. The debris instructions are the part people skip. GM says the case halves must be separated, the whole unit cleaned, and both the pump fluid filter and the control solenoid filter plate replaced, or you risk repeat damage. It also says not to wash the control solenoid valve body and TCM assembly in parts cleaner [1].

The coverage parts list gives you a realistic picture of the job: a service seal kit (24269586 for 2009 models, 24269587 for 2007-2008), four reverse clutch fibers (24238954), four flat steels (24258074), a 3-5-R backing plate (24236516), the reverse clutch housing and piston if required, and nine quarts of DEXRON VI (88861037). GM estimates that some of the additional hard parts are needed in about 25 percent of repairs [2]. Quote it that way.

Two more things protect the rebuild. ATRA recommends updated wave plates in every clutch, not just the one that broke: 1-2-3-4 (24259063), 2-6 (24259816), 3-5-R (24254103) and low-reverse (24259817), noting the 3-5-R breaks most [4]. And Sonnax points out that units with the updated, shot-peened OE plate, Gen 2 included, are still failing in the field because the plate keeps its teeth and every broken plate they studied separated at a tooth corner. Their 3-5-R drum saver kits pair a toothless waved plate with a billet cupped steel that locates it on the drum, which also lets you salvage a drum with chewed splines [5].

2. No movement after the wave plate repair (P2723)

This one is a builder error, and it comes straight out of problem 1. ATRA describes a no-drive and P2723 after a repair that included a new reaction planetary carrier, mostly on the GM crossovers and sedans that carry this unit [4]. Many publications draw the reaction carrier and input ring gear as one assembly. In reality the carrier, the input ring gear and the ring gear snap ring are serviced separately. Leave the ring gear off and it will not move. The fix is to install the ring gear [4]. If you are replacing a carrier damaged by wave plate debris, lay the old assembly next to the new one before it goes in the case.

3. 2014-2017 Equinox: launch shudder, flare and 2-3 shift complaints

The later Gen 2 Equinox has its own bulletin. GM 18-NA-358 covers 2014-2017 Equinox (RPO M7U, M7W), along with Terrain, Acadia, Enclave, Traverse, SRX and others, for a severe launch shudder in 1st from a stop, a shudder in 4th while cruising, or a shudder on the 2-3 upshift or 3-2 downshift, sometimes with flare, slide or bump, slip or harsh shift [3]. GM blames debris in the upper and/or lower valve bodies, or valves scratched or scored so they do not move properly [3].

The diagnosis order in that bulletin is worth following exactly:

• Rule out an engine misfire or driveability problem first.
• Rule out converter clutch shudder by watching TCC slip speed on the scan tool while the converter clutch is applied during the event. A shudder that lives in TCC slip is a converter problem, not this one.
• Try to reproduce the launch shudder with a power brake in first gear, for 5 seconds or less, so you do not stress the 1-2-3-4 clutch [3].
• If it reproduces, GM replaces both the upper and lower valve body assemblies at the same time (upper 24281084, lower 24257450, kit 24264343) [3].

Two warnings in the bulletin will save you money. GM says TEHCM replacement has not been an effective repair for this concern, so do not replace it if the problem is not misfire, driveability or TCC [3]. And inspect the input and output speed sensors for collected debris. Debris on the sensors is a sign of internal failure; no debris but scratched valves or bores means check the final drive bearing [3]. A new valve body on top of a failing final drive bearing just scratches the new one.

4. Delayed engagement and first-gear slip after a rebuild: mixed Gen 1 and Gen 2 parts

This is the Equinox-specific comeback. Transmission Digest wrote up a 2015 Equinox with the 3.6L that came back with a delayed engagement into Drive and slipping in first. Someone had installed a Gen 1 1-2-3-4 clutch apply piston in a Gen 2 transmission [6]. The Gen 2 piston's apply fingers are 0.147 in. taller: 0.785 in. versus 0.638 in. on Gen 1. With the short piston in a Gen 2 case, clutch clearance was too large for the pack to hold [6]. Gen 2 also thinned the 1-2-3-4 frictions to 0.058 in. from 0.061 in. on Gen 1 [6].

So on a 2013-2017 Equinox, measure the piston fingers and the frictions before assembly, and buy the kit for the generation on your bench. A 2013 truck could be either [4][6].

5. Bind on the 3-4 or 4-3 shift, possible P0797

ATRA lists a tie-up on the 3-4 or 4-3 shift on the 6T70 and 6T75, sometimes with P0797. A worn ring groove on the case cover hub sleeve lets the 3-5-Reverse and 4-5-6 clutch circuits cross-leak [4]. Pull the hub from the rear case cover, check the rings, and measure ring-to-groove clearance with a feeler gauge. Over 0.007 in., ATRA says replace the case cover [4]. This one is easy to miss if you only bag new sealing rings on a worn sleeve.

6. Things that look like problems but are not

ATRA notes that some 6T70 converters (RPO MH2, MH4, MH6 or MY9, which takes in the 2008-2009 Equinox) show dark or blue discoloration, often as circles on the hub side. If the whole converter is not discolored and there is no other evidence of overheating, do not replace it [4]. ATRA also lists a PRNDL display that does not show the selected gear on some GM applications, and an updated calibration for it [4]. Verify the gear on the scan tool before you call it a transmission fault.

Service and setup that keep an Equinox 6T70 alive

• Fluid: DEXRON VI [2]. Check the level on a level surface, parking brake on, engine idling after one minute, with transmission fluid temperature between 180 and 200 degrees F [4]. Reset the transmission oil life monitor after a change. ATRA's tip for getting to temperature is to drive it in 2nd [4].
• Interval: ATRA lists a fluid-only service at 100,000 miles normal and 50,000 miles severe. The filter is not a service item and is replaced only after an internal repair [4]. An Equinox that tows or does short-trip winter duty is severe service.
• After the repair: run Service Fast Learn Adapts with the scan tool, then shut the engine off and power down the TCM before restarting to finish it [4]. Any time you replace the transaxle, the internal TCM needs programming [4].
• Converter: lift it out vertically. There is no seal on the turbine shaft; the lip seal is inside the converter and is damaged if the converter goes in or out at an angle [4].

Quick reference

Need parts for this job?

Our 6T70 parts page has Gen 1 and Gen 2 rebuild kits, valve bodies, clutch drums, solenoid kits and filter kits that fit the V6 Equinox, all on our own checkout. For fluid specs across every unit, see the transmission fluid spec chart.

FAQ

Which Chevy Equinox has the 6T70 transmission?

The six-cylinder ones. The 2008-2009 V6 Equinox carries the 6T70 under RPO MH2 or MH4, and GM bulletin 18-NA-358 lists the 2014-2017 Equinox with the 6T70 under RPO M7U or M7W. Four-cylinder Equinox models use the smaller 6T40/45 family, and the 2018 and later Equinox dropped the V6 entirely, so check the RPO label before ordering parts.

Why does my Equinox have no reverse, 3rd or 5th gear?

On a 6T70 that pattern is almost always the 3-5-Reverse clutch. GM bulletin 09-07-30-012F traces it to a broken 3-5-R wave plate that lets the piston over-stroke and leak, usually with P0776 set. The repair is a teardown with updated plate 24254103, a full debris clean, a new pump fluid filter and a new control solenoid filter plate.

Is the Equinox 6T70 wave plate problem covered by GM?

GM special coverage 14404B covered 2008-2009 Equinox models with the 6T70 for 10 years or 120,000 miles from the in-service date, whichever came first. Every one of those vehicles is now past ten years, so the repair is a customer-pay job at an independent shop today.

Should I replace the TCM on a 2014-2017 Equinox that shudders?

Not on the first pass. GM bulletin 18-NA-358 says TEHCM replacement has not been an effective repair for the 1st-gear launch shudder, 4th-gear shudder or 2-3 and 3-2 shift complaint. Rule out misfire and converter clutch slip first; if the shudder can be reproduced with a short power brake in first, GM replaces both the upper and lower valve bodies.

What fluid does a 6T70 Equinox use?

DEXRON VI. GM's special coverage repair calls for nine quarts of DEXRON VI (part 88861037) for the clutch job. Check the level with the engine idling and transmission fluid temperature between 180 and 200 degrees F, and remember the internal filter is not a service item, so a fluid change is fluid only.