4L80E Overhaul Kit 1991-2013, new and ready to install. Fits the 4L80E. Ships fast from the USA.
For a budget reseal of any 4L80E built from 1991 through 2013, this kit carries manufacturer numbers 34002EX and KP34900E and supplies the gasket set, sealing rings, O-rings and lip seals in one box. It suits a Chevy or GMC 2500 or 3500, a Suburban 2500, an Express or Savana van or a Hummer H1 whose transmission drips on the driveway, slips once it is hot, or has a clutch pack you just replaced and now needs fresh rubber around it. It is also a sensible spare to keep on the shelf if you work on these heavy-duty units, or the TH400 they grew out of, more than once.
The 4L80E holds gears with four clutch packs and two bands, and every one of them depends on pressure staying where the valve body sends it. Gaskets seal the valve body, spacer plate, pump and case halves; sealing rings carry fluid from stationary parts into rotating drums; lip seals and O-rings let each piston build force against its plates. A tired seal turns into a leak path, and the clutch it feeds slips even when the plates are fine. This kit replaces that sealing layer. It does not include frictions, steels, bushings or a filter.
Sonnax explains that GM's slip code 1870 on the 4L80E sets when the computer sees too much slip between engine speed and transmission speed for several seconds. Worn seals can cause that, but so can a torque converter clutch or a pressure command fault. On 1994-up 6.5 diesel trucks, Transmission Digest points out that the accelerator pedal sensor is the main input for transmission line pressure, so a bad pedal sensor can cause low pressure and slipping with healthy seals. Work through those checks with the 4L80E Silverado 2500 shift problems guide, then gauge line pressure in every range. Correct pressure at the tap but slipping in one range means the leak is past the valve body, which is where these seals live.
The listing covers the 4L80E from 1991 to 2013. Over those years GM changed the pressure control solenoid, shift solenoids, harness connector and speed sensor arrangement for 1994, according to ATRA, and Sonnax shows the valve body changed again for 1997. A kit that spans the whole run therefore includes some seals your unit will not use, including drum lip seals that suit one design and not the other. Compare each new piece to the one you removed before installing it. If you would like us to verify the match, send the year and VIN. Other parts for your year are on our 4L80E parts page.
| Fits | 4L80E 1991-2013 |
| Part type | Overhaul Kit |
| Condition | New |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
The listing covers 1991 through 2013. Because the design changed in 1994 and again in 1997, some seals in the box will be extras for your unit; match each one to the part you removed.
It carries manufacturer numbers 34002EX and KP34900E.
No. It is a gasket, sealing ring, O-ring and lip seal kit. Clutches, steels, bushings and the filter are separate.
Only when the slip comes from leaking seals. Sonnax notes 1870 means the computer detected too much slip, so check the converter clutch, pressure control and, on 6.5 diesels, the pedal sensor before rebuilding.
GM's 2006 Silverado owner manual gives about 180 to 200 F as normal. Running hotter for long periods ages the seals this kit replaces.
