4L80E Shift Kit 1991-09, new and ready to install. Fits the 4L80E. Ships fast from the USA.
Working trucks are where the 4L80E earns its keep, and they are also where it burns up the direct clutch. If your Silverado or Sierra 2500 or 3500, Suburban 2500, or Express or Savana van with the 4L80E or 4L85E slips on the 2-3 shift when it is loaded, comes back from a rebuild with the same complaint, or sets P0894 or a solenoid performance code, this is the fix professional rebuilders reach for. This listing is a new, boxed TransGo 4L80E-HD2 reprogramming kit, cataloged for 1991-2009 vehicles here and by TransGo for 1991 to 2013.
Third gear in a 4L80E comes from the direct clutch, which stays applied in fourth and in Reverse, so it does a lot of work in a towing truck. TransGo calls it the weak point of the transmission. The HD2 answer is a laminated triple separator plate that feeds the direct clutch from two circuits. TransGo says that triples the clutch's holding capacity without taking the transmission apart. The rest of the kit is valve body, pump and internal parts matched to a higher line pressure curve, so clutches go on firmly instead of slipping.
Pressure control is the other half. The boost valve wears in its bushing, and TransGo says that can go two ways: low boost pressure gives soft 2-3 shifts and cooked direct plates, while runaway boost pressure can crack the case and break the direct drum and piston. The kit replaces the valve and bushing with a hardened, wide land design and adds an EPC boost relief valve so pressure cannot run away.
A shift kit fixes hydraulics, not electrical faults. On the 1999-2009 trucks, GM's diagnostic data ties P0751 and P0756 to stuck shift patterns that a dead solenoid or a broken pass-through connector will also cause, so test those first using the 4L80E Silverado 2500 shift problems guide. Van owners should also read the 4L80E Express van problems guide, because harness and heat issues are common there. If the direct clutch has already failed, install this kit during the rebuild, not on a unit that is still slipping.
This listing is cataloged for 1991-2009, which covers the GMT400 trucks, the 1999-up GMT800 2500 and 3500 pickups with the 6.0L and 8.1L, and Express and Savana vans through 2009. The same TransGo part number is listed by TransGo for 1991 to 2013 4L80E and 4L85E transmissions. GM changed valve bodies, pressure control solenoids and accumulators over those years, so follow the TransGo instructions for your build year. Send us your year and VIN if you are not sure. Everything else for this transmission is in the 4L80E collection.
| Fits | 4L80E 1991-09 |
| 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.
Yes, if the truck has the 4L80E. GM used the 4L80E behind the 6.0L and 8.1L in the Silverado and Sierra HD, and TransGo lists this kit for 1991 to 2013 4L80E and 4L85E units.
It is the same TransGo 4L80E-HD2 kit. Our catalog entry covers 1991-2009 vehicles, and TransGo lists the kit for 1991 to 2013 transmissions.
The main reprogramming, including the triple separator plate that dual feeds the direct clutch, is done without dismantling the transmission. The snap rings and return springs only go in when the unit is apart.
TransGo lists P0894 among the codes the kit addresses when the cause is hydraulic slip. Check for worn clutches, a failed solenoid or wiring first.
If it is original or the pressure readings are off, yes. The pan is already down and the kit works with a raised line pressure curve that depends on a healthy EPC solenoid.
