Complete 4L80E and 4L85E master rebuild kit with friction plates, steel plates, gaskets, seals and O-rings for GM 3/4-ton and 1-ton trucks and vans.
This is the kit for the heavy-duty GM four-speed that has finally given up behind a working truck: a 2500 or 3500 Silverado or Sierra pulling a trailer, a Suburban 2500 or Yukon XL, an Avalanche 2500 with the 8.1L, or an Express or Savana van loaded to the roof. When the 4L80E or 4L85E starts flaring between gears, takes too long to grab Reverse, or drops a pan full of black fluid and friction dust, this one box supplies the friction plates, the steel plates, and the overhaul gasket and seal set with its lip seals and O-rings. Shipping weight is 13.9 lb, and the listing carries reference number 8675545.
The 4L80E is a TH400-based three-speed core with an overdrive section added in front, all shifted by the computer. Five clutch packs (overdrive, overrun, forward, direct and intermediate) plus the low/reverse band do the work, and each clutch clamps its frictions against steels using line pressure carried through rubber seals and sealing rings. The 4L85E is the higher-torque version built in the same case, so it rebuilds with the same soft parts. Because a cooked pack nearly always heat-marks or cups its steels as well, replacing frictions and steels together is what gives you a correct stack to measure from, and the new seals are what let the rebuilt unit hold the pressure those clutches need.
Make sure something outside the transmission did not cook the clutches, or the new ones will go the same way. On 1994-and-later 6.5L diesel trucks, Transmission Digest explains that the pedal position sensor sets both fueling and line pressure, so an injection pump that leaks extra fuel lets the truck pull away on very little throttle and the computer commands too little line pressure, burning the forward, intermediate and direct clutches. On gas trucks, a weak pressure control solenoid can do the same; our 4L80E pressure control solenoid guide shows how to test it, and the 4L80E common problems and fixes guide covers splitting a complaint into hydraulic, electrical and mechanical causes. For a no-Reverse truck, test line pressure in Reverse, third, fourth and manual first: if third and fourth work, the direct clutch can still apply. Good pressure with slipping still present confirms the overhaul.
The listing covers the 4L80E and 4L85E across the 1991-2009 production span, with examples given for 1999-2007 Silverado and Sierra 1500 HD, 2500, 2500 HD and 3500, Suburban and Yukon XL 2500, Express and Savana 2500 through 4500, and the 8.1L Avalanche 2500, including 6.0L, 8.1L and 6.5L diesel powertrains. GM moved the cooler return to the center support in 1997 and redesigned a number of internal parts around it, so a pre-1997 unit is a different build from the trucks named above. Read the ID tag on the case, then match it to your truck, or send us the year and VIN before ordering. Every year-specific 4L80E part we carry is on the 4L80E parts page, and owners of the newer trucks will find the usual failure list in our Silverado 2500 4L80E problems guide.
This kit renews the soft parts only, so inspect every hard part before reassembly: pump gears and bushings, drum bores and seal grooves, the overdrive roller clutch, the intermediate sprag, and the planetary carriers. Soak the new frictions in ATF for at least 30 minutes, coat piston seals with assembly lube so the lips do not roll when the pistons go home, and set each clutch pack clearance with a feeler gauge rather than trusting a plate count. Refill with Dexron VI. If the old pressure control solenoid is suspect, install a new 4L80E pressure control solenoid while the pan is off. Trucks that tow hard benefit from extra fluid capacity, which is the reason buyers pair a rebuild with the TCI cast aluminum deep pan. GM's own 2006 Silverado owner manual puts normal transmission temperature at about 180 to 200 F, with a protection mode near 265 F, so watch the gauge on the first loaded trips.
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Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes. The listing covers both. The 4L85E is the higher-torque version of the same case and uses the same overhaul soft parts, but always read the ID tag on the transmission and match it before ordering.
Friction clutch plates, steel clutch plates, and the overhaul gasket and seal set with lip seals and O-rings. It does not include hard parts such as drums, bushings, the pump, sprags or planetary carriers, so inspect those during teardown.
Only if the cause is gone. On 1994-and-later 6.5L trucks a leaking injection pump can make the computer command too little line pressure, which burns the forward, intermediate and direct clutches. Check the engine side first or the new clutches will fail the same way.
Use Dexron VI ATF, and soak every new friction plate in ATF for at least 30 minutes before you stack the clutch packs.
It can, because Reverse uses the direct clutch and the low/reverse band. Pressure test in Reverse, third, fourth and manual first first. If third and fourth work, the direct clutch can apply, and the problem may be the band, the servo or the valve body instead.
The listing names 1999-2007 Silverado and Sierra 1500 HD, 2500, 2500 HD and 3500, Suburban and Yukon XL 2500, Express and Savana 2500-4500 vans, and the Avalanche 2500 with the 8.1L. Send your year and VIN if your truck is outside that list.
