Master overhaul kit with frictions, steels, seals, gaskets and filter for the GM 6L80E and 6L90E six-speed in Silverado, Tahoe, Camaro and Corvette.
This is the overhaul kit for a GM 6L80E (RPO MYC) or 6L90E (RPO MYD) that has already come out of the truck: slipping in third, fifth and reverse, a burned smell on the dipstick tube, or a pan full of friction material and aluminum glitter after a converter let go. It packs the friction and steel clutch plates, the full seal and gasket set and a new filter, and it cross-references to GM 24236931 and 34664P. Listed applications run from the 2006 Escalade and Corvette through Silverado and Sierra 1500-3500, Tahoe, Yukon, Express and Savana vans, Hummer H2, CTS and CTS-V, Camaro SS, Pontiac G8, and heavy-duty 6.0L and 6.6L trucks up to 2022.
The 6L80 makes six forward gears with five clutches: 1-2-3-4, 3-5-Reverse and 4-5-6 in the input drum area, plus 2-6 and Low/Reverse in the center support. Every shift is a clutch-to-clutch handoff timed by the TCM, so worn frictions do not just slip, they throw off the computer's fill timing and show up as flares and harsh shifts first. A master kit replaces every friction and steel in all five packs and every rubber and Teflon seal in one job, so the unit leaves the bench with matching clearances and fresh sealing instead of a mix of new and used.
ATRA's GEARS magazine points out that most 6L80 failures are pressure related, so test before you pull it. Put a gauge on the mainline port on the passenger side and compare actual pressure to the EPC command on a scan tool. Low pressure that rises with engine speed suggests a pump problem; good pressure with slipping gears means worn clutches. GM's own advice for some harsh downshifts is simply a Reset Transmission Adapts, so rule that out first. Our 6L80 common problems guide and 6L80 pump failure symptoms guide walk through the pressure and noise checks.
The kit is listed for 2006 and later 6L80E and 6L90E units in the vehicles named above. Clutch counts and some parts differ between the two models and across model years, so confirm by RPO code on the glovebox or door sticker: MYC is a 6L80, MYD is a 6L90. Sonnax notes the 6L90 case is 1-3/8 inch longer with roughly 25 percent upgraded internals, which is why the RPO matters when you count plates. If you are unsure, send us the year and VIN and we will match it before it ships. The rest of our hard parts are in the 6L80 parts collection.
Most 6L80s arrive on the bench because the converter failed, which means the pump took the debris. Inspect it even if it looks clean: GEARS gives pump slide and rotor clearance as 0.0008 to 0.002 inch, best checked with Plastigage, and warns that a machined stator or bell housing adds to unit endplay, which should land at 0.004 to 0.006 inch. Soak every friction in Dexron VI before assembly and check each pack clearance. Resize the input shaft sealing rings with a 6L80 seal ring expander and resizer rather than forcing them, and replace worn bushings with a 6L80 bushing driver kit. Flush the cooler hot or replace it, because debris hides in the lower rows. Fill with Dexron VI through the check plug, then reset adapts and complete a fast learn.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes, it is listed for both the 6L80E and 6L90E. Confirm your unit by RPO code (MYC for 6L80, MYD for 6L90) because plate counts differ, and send us your VIN if in doubt.
Friction plates, steel clutch plates, the seal and gasket set, and a new filter. It cross-references to GM 24236931 and 34664P. Hard parts such as drums, pistons, the pump, valve body, TEHCM and torque converter are not included.
Inspect the pump and stator, bushings, wave plates and the input drum. Service or replace the torque converter, since a failed converter is the usual reason these units come apart, and flush or replace the cooler.
Dexron VI. The 6L80 has no dipstick, so fill through the case and set level at the check plug at operating temperature.
Yes. Reset transmission adapts and run the fast learn so the TCM relearns clutch fill on the new frictions. Skipping it leaves harsh or flared shifts based on old learned values.
