4L80E Overhaul Kit 1997-2011, new and ready to install. Fits the 4L80E. Ships fast from the USA.
If your 1997 or later 4L80E is out of the truck and on the bench, every gasket, piston seal and sealing ring you take off has to be replaced before it goes back together. This kit is that rubber and paper for the later 4L80E used behind the 6.0L, 8.1L and diesel engines in Chevrolet and GMC 2500 and 3500 pickups, Suburban 2500, Express and Savana vans and the Hummer H1. It is the right buy for a truck that weeps fluid from several places at once, takes a long pause before it grabs Drive on a cold morning, or starts to slip once it is hot and loaded. The listing cross-references this kit to W34002EA and the KP34900FX interchange number, so a shop parts sheet that calls out either one is pointing at this part.
The 4L80E is a hydraulic machine. Line pressure from the front pump travels through the case, through the valve body separator plate, across rotating sealing rings and into the forward, direct, fourth, intermediate and overrun clutch pistons. Every handoff is sealed by something soft. Pan and valve body gaskets keep the circuits apart, lip seals and O-rings let the pistons hold pressure, and the sealing rings bridge oil from stationary parts into spinning drums. After years at operating temperature that rubber hardens and shrinks, and each leak point bleeds a little apply pressure away. This kit is a reseal only. There are no friction plates, steel plates, bands, bushings or filter in the box, so plan on sourcing those separately for a full rebuild.
Sonnax lists loss of oil pressure in worn critical circuits as the root cause behind a long list of 4L80E complaints, including 3-4 neutral, no fourth and burnt clutches. Fresh seals are half of that fix; worn valve body bores are the other half. Our 4L80E common problems guide walks through which complaints are seals and which are hydraulic.
Check fluid level and condition first. Then put a pressure gauge on the line port and compare idle and stall readings in each range against the factory chart. Low pressure in one range only points to a leak in that clutch circuit, which is a seal job. Low pressure everywhere points to the pump, the pressure control solenoid or the valve body. Rule out the electrical side with our 4L80E EPC solenoid symptoms guide before tearing the unit down.
This kit is listed for the 1997-2011 4L80E and fits the later-design units built after GM's 1997 revisions. It is not the correct choice for a 1991-1996 4L80E, which has its own seal and gasket differences. Because GM made running changes through these years, check the transmission identification tag and compare your old parts against the kit at teardown, or send us your year and VIN and we will confirm it before shipping. Every 4L80E part we carry is on the 4L80E collection page.
| Fits | 4L80E 1997-2011 |
| Part type | Overhaul Kit |
| Condition | New |
| Brand | GM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. This is a gasket and seal overhaul kit: gaskets, piston seals, O-rings and sealing rings. Frictions, steels, bands, bushings and the filter are sold separately.
This kit is listed for 1997-2011 units. The 1991-1996 4L80E uses a different kit, so check our 4L80E collection for the earlier version or send us your year and VIN.
Only if the clutches are still good and the slip comes from pressure leaking past old seals. If the plates are burnt or the valve body bores are worn, a reseal alone will not hold.
Dexron VI. GM's 2008 Express owner manual lists DEXRON-VI and a 7.7 quart service capacity for the 4L80E. A full rebuild with a dry converter takes more.
The listing cross-references this kit to KP34900FX and W34002EA, which are the interchange numbers for the 1997-2011 4L80E overhaul gasket and seal kit.
