4L85E Shift Kit 1991-2009, new and ready to install. Fits the 4L85E. Ships fast from the USA.
This listing is for builders working on a 4L85E out of a 2002 to 2009 heavy-duty GM: Silverado and Sierra 2500HD and 3500, Express and Savana vans, and the 8.1L and 6.0L trucks that leaned on this transmission hardest. The usual complaint is a 2-3 shift that slips when the truck is loaded, followed by a burned direct clutch. What you get is a new TransGo SK valve body repair kit in the white TransGo box, which fixes the hydraulic causes of that failure. It is the standard SK kit, not the HD2 plate kit.
GM built the 4L85E with five-pinion planetaries to survive heavier loads than the 4L80E, but it kept the same valve body and pressure circuit. So the geartrain got stronger while the weak points in the hydraulics stayed. The boost valve, which converts the EPC solenoid signal into extra line pressure, wears its bushing; low boost means the direct clutch applies too gently on the 2-3 shift and glazes, and stuck high boost can split the case. TransGo's fix is a hardened wide land boost valve and bushing, a relief valve that caps EPC boost, new regulator and accumulator springs, and cup seals for the direct and reverse feed holes. Net effect: a little more line pressure and quicker, cleaner clutch apply.
Several of those codes have electrical causes too. Before ordering, measure the shift solenoids and check line pressure with a gauge. Our 4L85E common problems guide lists the failures that look like a pressure problem but are not, and the filter and pan service guide shows what to look for in the pan, since clutch material and broken filter pieces tell you whether the unit needs the kit alone or a full rebuild.
The catalog range here runs 1991-2009, but the two halves of that range are different transmissions. The 4L85E (RPO MN8) entered production in 2002, so on a 4L85E this covers 2002-2009 trucks and vans; 1991-2001 trucks used the 4L80E, which the same kit also fits. TransGo itself lists the SK for 1991-2013 on both units. Two GM changes matter: 1997-up units use center-support lubrication, and the instructions treat some valve body steps by year. Check the RPO sticker in the glove box or send us the year and VIN to confirm. All parts are in the 4L85E collection.
| Fits | 4L85E 1991-2009 |
| Part type | Shift Kit |
| Condition | New |
| Brand | TransGo |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
If the truck has the 4L80E or 4L85E, yes. TransGo lists the SK kit for every 1991-2013 4L80E and 4L85E. Check the RPO codes in the glove box for MN8 (4L85E) or MT1 (4L80E).
The kit is shared with the 4L80E, which was used from 1991. On a 4L85E the applicable years in this range are 2002 to 2009.
No. This is the SK kit, which has no separator plate. The HD2 adds a laminated triple separator plate that dual feeds the 3rd gear clutch and runs a higher pressure curve.
Not by itself. If the direct clutch is burned it must be rebuilt. Install the kit during that rebuild so the new clutches get proper apply pressure.
The kit is hydraulic, so no programming is required, but clearing codes and resetting adaptive learn after a valve body service lets the PCM adapt to the new shift feel.
