4L80E Shift Kit 1991-2000, used and ready to install. Fits the 4L80E. Ships fast from the USA.
Note first: despite the shift kit name on this listing, the part you receive is not a valve body shift kit. It is a used 4L80E overdrive planet kit for 1991 through 2000 transmissions, made up of the overdrive planet, the drum, the early black type sprag and the input shaft. It is the repair for a 1991-2000 Chevrolet or GMC 2500 or 3500, Suburban 2500, Express or Savana van, or Hummer H1 that suddenly will not pull in Drive, has started to howl at road speed, or left chewed-up rollers in the pan. Before it was listed, the drum was taken apart and checked for play, the clutches and steels inside were judged to be in good used condition, the input shaft was rolled to confirm it is straight, the splines were inspected, and the planet teeth were checked for chips.
The front of every 4L80E is a simple overdrive gearset that feeds a three-speed geartrain behind it. The input shaft brings turbine torque into the overdrive planet. In first, second and third with the selector in the overdrive position, a one-way roller clutch locks that planet so the front section turns as one piece and passes engine speed straight back to the forward drum. Sonnax points out that the roller clutch is built into the parts in this kit: the overrun clutch drum is its inner race and the bore of the overdrive planet is its outer race. That is why one failure usually ruins both pieces, and why they are sold here as a matched set.
The weak spot is that in the overdrive range the roller clutch carries the load alone. The overrun clutch is only applied in manual 3, 2 and 1. Transmission Digest describes heat as the other killer: in an overheat the plastic roller cage can melt, and the clutch fails quickly. Snow plow, salt spreader and heavy tow trucks see this most.
Drive the truck in D and then in each manual range. If the transmission only loses the overdrive range, the roller clutch is the prime suspect. Drop the pan and look for roller pieces and plastic. A ratio code by itself is not proof, because a weak speed sensor signal or a failed solenoid can mimic slip, so rule those out with our 4L80E shift solenoid diagnosis guide. The 4L80E common problems guide covers the overdrive failure in more depth.
This kit is for 4L80E transmissions built 1991 through 2000 that use the early black sprag overdrive design. GM changed these parts for 2001 and later units, so a later transmission needs the 2001-and-up overdrive planet kit instead. Do not mix early and late pieces. Trucks often get a replacement transmission over the years, so go by the ID tag on the case rather than the model year of the vehicle, or send us your year and VIN and we will check it before it ships. Other hard parts for this unit are on the 4L80E parts page.
| Fits | 4L80E 1991-2000 |
| Part type | Shift Kit |
| Condition | Used |
| 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.
No. Despite the listing name, this is a used 4L80E overdrive planet kit for 1991-2000: overdrive planet, drum, black sprag and input shaft. If you need a valve body shift kit, look at the TransGo 4L80E kits in our 4L80E collection.
No. 2001 and later units use a later overdrive design. Order the 2001-and-up overdrive planet kit, and do not mix early and late parts.
In the overdrive range the one-way roller clutch holds first through third by itself. In the manual ranges the overrun clutch applies as well, so a failed roller clutch often still drives in 2 and 1.
Check the forward drum ring gear for damage, replace seals, frictions, worn bushings and thrust washers, and flush the cooler and lines so debris from the failure is gone.
Dexron VI, checked with the transmission at operating temperature.
No. It is used and was inspected before listing: drum checked for play, input shaft checked for straightness, splines and planet teeth checked.
