6L80E Master Overhaul Rebuild Kit for GM Trucks 2006-Up

This master overhaul kit is for the GM six-speed rear-wheel-drive automatic in both its forms: the 6L80E behind the gas V8s in half-ton trucks and SUVs, and the 6L90E used in heavy-duty pickups, larger Express vans and the CTS-V. It is the kit to reach for when an Escalade, Yukon, HD Silverado or Sierra, or an Express van has a transmission that slips, bangs into gear or leaks internally and you have decided to take it all the way apart. One box covers both units, which is handy for fleet and van work where the same shop sees both RPO codes every week.

What a master overhaul kit does in a 6L80E or 6L90E

These transmissions are clutch-to-clutch units: no bands, five clutch packs and a low one-way clutch, all applied by hydraulic pressure that the TCM on the valve body controls. Every shift is a handoff where one clutch releases while the next one fills. That makes the seals and frictions far more important than in an older band-type transmission, because a single leaking ring or glazed friction pack changes fill time and the controller has to compensate. A master overhaul kit replaces the gaskets, seals, sealing rings and friction plates throughout the unit, so pressure holds in every circuit and every clutch starts from the same fresh surface. The 6L80E and 6L90E share the internal clutch layout, which is why one kit can serve both.

Symptoms that point to a full overhaul

• Slipping in more than one gear, or slipping that gets worse with heat and towing
• Late or harsh engagement into Drive and Reverse
• Reverse slip or 2-3 flare from a worn 3-5-R pack, and lost upper gears from the 4-5-6 clutch
• Black fluid and friction debris in the pan
• Converter shudder that ran long enough to contaminate the fluid and the valve body
• Clutch or ratio codes such as P0751 that return after an adapt reset

How to confirm before you buy

A kit cannot fix a valve body, solenoid or wiring fault, so prove the clutches are the problem first. Read the codes, check the level hot at the check plug, and pull the pan. Low line pressure from a damaged pump can look like every clutch slipping at once, and GM has documented pump pressure spikes that split the filter on a cold start. A shudder on its own is often worn-out fluid. The 6L80 common problems and fixes guide covers those cases in order, and the 6L80 Escalade shift problems guide applies directly to the full-size SUVs on this fitment list.

Fitment

The listing names these applications: Escalade and Escalade ESV 2006-2018 and Escalade EXT 2006-2013; Yukon and Yukon XL 1500 2006-2020 and Yukon XL 2500 2006-2013; Silverado and Sierra 2500HD and 3500HD 2007-2022 with the 6L90E; Express 1500 and 2500/3500 2009-2021 and Express 4500 2010-2019; Cadillac CTS 6.0L 2007-2015, CTS-V 6.2L 2008-2015 and STS-V 4.4L 2006-2009. The 6L80 and 6L90 share their clutch layout, but the 6L90 has a longer case, a different output shaft and heavier internals, so on teardown count the plates in each pack and compare them with the kit before building. Read the RPO code on the glovebox label (MYC is the 6L80, MYD is the 6L90), or send us your year and VIN. Everything we stock for this family is on the 6L80 transmission page.

Install notes

• Lay each clutch pack out in order as it comes apart, inspect steels for heat marks and replace any that are blued or warped.
• Check the pump gears and bushing. A scored pump undoes the overhaul, so swap in a 6L80 pump if the old one is worn.
• Clean or replace the valve body and its screens. If the unit has a worn bore history, a valve body end plug kit fixes the common plug leaks while it is on the bench.
• On 2014-and-later units, replace the thermal bypass valve; GM's later valve opens at a lower temperature than the original.
• Soak frictions in Dexron VI, set every clearance to the service manual, then fill with Dexron VI and set the level hot at the check plug.
• Reset adapts and run the learn procedure before road testing under load.

Does this kit fit both the 6L80E and the 6L90E?

Yes, it is listed for both. They share the internal clutch layout. Because the 6L90 has heavier internals, compare the plate count in each pack with the kit on teardown before assembly.

How do I tell whether my truck has a 6L80 or a 6L90?

Look at the RPO codes on the service parts label in the glovebox or console. MYC is the 6L80 and MYD is the 6L90. Heavy-duty 2500 and 3500 pickups use the 6L90.

Is a Silverado 1500 or Tahoe covered?

The kit is built for the 6L80E those trucks use, but the listing's named vehicle list focuses on Escalade, Yukon, HD trucks, Express and Cadillac cars. Send us your year and VIN and we will confirm before you order.

What should I replace along with the kit?

Any heat-marked steels, worn bushings, a scored pump, and on 2014-and-later units the thermal bypass valve. Clean or replace the valve body so debris from the failure does not ruin the new clutches.

What fluid and how much?

Dexron VI. A pan and filter change on a 6L80-E truck is about 6.0 quarts, but a dry rebuilt unit takes considerably more, so fill and then set the level hot at the check plug.

Do I need a scan tool after the rebuild?

Yes. Reset transmission adapts and run the learn procedure so the TCM learns the fill times of the new clutches.

• 6L80 Common Problems and Fixes: The Seven Failures That Actually Show Up
• 6L80 Escalade Shift Problems: Diagnosis and Fix
• 6L80 Escalade Common Problems and Fixes
• 6L80 Pump Failure Symptoms and Replacement