6L80 Banner Rebuild Kit 2006-2021

This banner overhaul kit, part number KP3300JAX in the version without pistons, covers the 6L80 across its whole run from 2006 through 2021 in Chevrolet, GMC, Cadillac and Hummer vehicles. It is the right buy when your 6L80 is slipping, engaging late or leaking from internal seals and your teardown shows the bonded pistons are still soft and sealing. You get the overhaul gasket and seal set, new frictions and a filter, and you keep the money a piston kit would cost for parts that may not need it.

What a banner kit does in a 6L80

Inside a 6L80, each of the five clutches is applied by a piston with its sealing lip molded onto the piston body, and fed by Teflon rings on the input and output shafts. The banner kit replaces the rings, the case and pump gaskets, the shaft seals and every friction plate, which are the parts that wear out first in a normal-mileage unit. The pistons are left out on purpose. Many 6L80s come apart with pistons that still pass an air check, and replacing them adds cost without changing the result. The trade-off is that you have to inspect them honestly.

Symptoms this kit is meant for

• Slipping or a delayed shift into gear once the fluid warms up
• 3-5-R or 4-5-6 friction wear showing up as reverse slip, a 2-3 flare or lost upper gears
• Burnt fluid that a change did not fix
• Internal leakage, with clutch ratio codes such as P0751 after adapts have maxed out
• A high-mileage unit coming out for another reason, such as a converter or front seal job, that is due for a reseal

How to confirm and judge the pistons

Before buying any rebuild parts, rule out the valve body and pump. Worn actuator feed limit valve bores produce erratic solenoid supply pressure, wrong-gear starts and clutch codes on a transmission with good clutches. The 6L80 Corvette shift problems and 6L80 common problems and fixes guides lay out those checks. Once the unit is apart, press a fingernail into each piston lip. A lip that is hard, cracked or flattened on one side will not seal, and that unit needs pistons. If you find that, our 6L80E rebuild kit with pistons is the better choice.

Fitment

The kit is listed for 2006-2021 6L80 transmissions in Cadillac, Chevrolet, GMC and Hummer applications: Silverado and Sierra, Tahoe, Suburban, Yukon, Escalade, Camaro and Corvette among them. Over 15 years GM revised parts of this unit, including some clutch plate counts, so count the plates in each drum on teardown and compare them with the kit before you begin assembly. Heavy-duty trucks with the 6L90 are a different case length, so confirm your RPO code (MYC for the 6L80) on the service parts label, or send us your year and VIN. Browse everything for this transmission on the 6L80 transmission page.

Install notes

• Size new shaft sealing rings before installing the input housing. The 6L80/6L90 seal ring expander and resizer keeps them from being cut on assembly.
• Replace bushings that show copper or scoring while the case is bare. A 6L80 bushing driver kit installs them to the right depth.
• Inspect steels for flatness and heat marks, and replace any that are blued.
• Soak frictions in Dexron VI, air-check each clutch and set clearances with selective plates.
• There is no dipstick. Fill with Dexron VI ATF and set the level at the check plug with the engine running and fluid at operating temperature.
• Clear adapts and run the learn procedure with a scan tool before the vehicle goes back into service.

What does without pistons mean?

The kit includes the overhaul gaskets and seals, frictions and a filter, but not the bonded clutch apply pistons. Reuse your pistons only if their sealing lips are still soft and pass an air check.

Does this kit fit every 6L80 from 2006 to 2021?

It is listed for 2006-2021 6L80 units in Chevrolet, GMC, Cadillac and Hummer vehicles. GM changed some plate counts over the years, so compare the kit with your drums on teardown or send us your year and VIN.

Can I use it on a 6L90?

It is listed as a 6L80 kit. The 6L90 has a longer case and heavier internals, so confirm your RPO code first. MYC is the 6L80 and MYD is the 6L90.

What else should I buy with it?

Plan on steels for any burned pack, bushings that are worn through, and Dexron VI fluid for the refill. If your pistons are hard or cracked, choose a kit that includes pistons instead.

What fluid does the 6L80 use?

Dexron VI. The level is checked at the case check plug with the fluid hot, since the 6L80 has no dipstick.

• 6L80 Corvette Shift Problems: Diagnosis and Fix
• 6L80 Common Problems and Fixes: The Seven Failures That Actually Show Up
• 6L80 Corvette Common Problems and Fixes
• 6L80 Camaro Common Problems and Fixes