6T70 Overhaul Kit 2007

The 2007 model year was the first for GM's 6T70, and the first-year units are the ones that taught every transmission shop about the 3-5-Reverse wave plate. If you are rebuilding a 2007 GMC Acadia, Saturn Outlook or Aura, or Pontiac G6 because it lost reverse, 3rd and 5th, slips when hot, or leaks from the case, this new overhaul kit supplies the seals and gaskets for the job. The photo shows the kit in its envelope packaging from a dedicated transmission parts brand, built as a sealing kit rather than a clutch kit.

What the overhaul kit does in an early 6T70

Every clutch in a 6T70 is applied by a rubber-sealed piston, and the TEHCM controls each apply directly with no shift valves to fall back on. When a seal leaks, the clutch applies soft or late and the computer can only compensate so far. On the first-generation units the seal kit matters more than usual, because the most common early failure ends in a torn seal. GM's bulletin explains the chain: the waved cushion plate in the 3-5-Reverse clutch cracks, the apply piston over-strokes, the piston seal leaks, and the clutch loses apply. Replacing the plate alone and reusing that piston seal sends the truck right back. An overhaul kit gives you every piston seal, sealing ring, gasket and O-ring so the whole unit is resealed while it is apart.

Symptoms on a 2007 unit

• No reverse, no 3rd and no 5th, often with P0776 and a check engine light. GM notes P0777, P2723, P0717, P0716, P2715 and P2714 can also set from the debris.
• Slow, soft engagement into gear when cold.
• Slipping or flare on upshifts after the fluid is hot.
• ATF leaks at the side cover or between the case halves.

How to confirm before you buy

ATRA's quick check for the no-reverse complaint is to unplug the transmission and see whether reverse engages; if it does, the problem is electrical, not the wave plate. Pull the pan and look for metal and clutch debris. Our Acadia common problems guide walks the early failures year by year, and the Malibu common problems guide covers the same failures in the 2008-up sedan.

Fitment

This listing is for the 2007 6T70, a Gen 1 transmission. GM itself split the factory seal kit by year in Special Coverage 14404B, one kit for 2007-2008 and a different kit for 2009, so year matters even within Gen 1. Sonnax also shows that 2007-2008 valve bodies use a different 3-5-R regulator valve than 2009-later and that the two do not interchange, a reminder that early units have their own parts. If your vehicle has the heavy-duty 6T75, use the 2007 6T75 overhaul kit. Check the RPO code on the glovebox label, or send us your year and VIN to confirm. More early-unit parts are on the 6T70 collection page.

Install notes

• Soak the new seals in DEXRON-VI and gel the sealing rings before assembly.
• Inspect the 3-5-Reverse drum splines and the backing plate. GM's coverage list adds reverse fibers, steels, the backing plate, and the housing and piston if needed. A worn drum calls for the 2007 6T70 clutch drum.
• GM's bulletin says to clean the entire unit and replace the pump fluid filter and control solenoid filter plate to prevent repeat damage. Do not wash the TEHCM in solvent.
• Use a new side cover gasket and install the converter vertically to protect its internal lip seal.
• Plan on about nine quarts of DEXRON-VI, check the level hot, and run Service Fast Learn Adapts. A 2007 6T70 shift kit can go in during the same teardown.

Which vehicles used the 6T70 in 2007?

The first applications included the GMC Acadia, Saturn Outlook and Aura, and Pontiac G6. Some of these trucks used the heavy-duty 6T75, so confirm the RPO code before you order.

Will this kit fix no reverse, 3rd or 5th?

It supplies the seals that the failure damages, but the cause is usually a broken 3-5-Reverse wave plate. Replace the wave plate and inspect the drum, piston and backing plate as well.

Can I use a 2009 kit on a 2007 6T70?

Not safely. GM listed separate seal kits for 2007-2008 and for 2009 models, so match the kit to your year or send us your VIN.

Does it include friction plates?

No. An overhaul kit is gaskets, seals, sealing rings and O-rings. Clutch frictions and steels are bought separately or in a master kit.

How much fluid does the rebuild need?

GM's coverage parts list calls for nine quarts of DEXRON-VI. Fill, run the engine, and set the final level hot.

• 6T70 Acadia Common Problems and Fixes
• 6T70 Malibu Common Problems and Fixes
• 6T70 Common Problems and Fixes
• 6T70 Acadia Shift Problems: Diagnosis and Fix