4L80E Clutch Module 1991-2001, remanufactured and ready to install. Fits the 4L80E. Ships fast from the USA.
A 4L80E plow truck, tow rig or work van that suddenly will not pull in Drive after a hard, hot day, yet still moves in manual 2 or 1, has very often lost its overdrive one-way clutch. This is a remanufactured overrun clutch assembly for 1991-2001 4L80E transmissions, supplied with the overdrive sun gear and the one-way clutch (often called the sprag) already in it. It replaces the front overdrive section in one piece instead of rebuilding a heat-damaged drum from loose parts.
The front of the 4L80E is an overdrive planetary that either turns at 1:1 or steps the speed up for fourth gear. In first, second and third the one-way roller clutch inside the overrun clutch drum locks the overdrive planetary so it passes engine power straight through. In fourth it freewheels while the fourth clutch holds the sun gear. The overrun clutch is a friction pack in the same drum that only applies in the manual 2 and 1 positions, where it backs up the roller clutch and gives engine braking. In regular Drive the roller clutch carries the full load on its own.
That is the weak point. Transmission Digest's Sonnax TASC Force write-up on 4L80E overdrive failures notes that the roller clutch fails more often in this unit than in comparable Ford designs, and that overheating can melt its plastic cage, which leads to a fast failure. Snow plowing and heavy towing in Drive are the classic causes.
Do a range check first. If the truck moves in 2 and 1 but not in Drive, the overdrive section is the prime suspect. Pull the pan and look for plastic and roller debris before you blame a solenoid. Line pressure should also be checked, because low pressure can mimic a slip in several ranges. Our 4L80E common problems guide breaks down the overdrive roller clutch failure, and the Silverado 2500 shift problem guide helps rule out electrical causes.
This assembly is listed for 4L80E transmissions from 1991 through 2001, used in Chevrolet and GMC 2500 and 3500 pickups, Suburban 2500, Express and Savana vans and the Hummer H1 in those years. Because it is a remanufactured hard part, compare it with your old drum before installing: the sun gear tooth count and length, the drum's spline and the bushing sizes should all match. If in doubt, send us your year, VIN and a photo of the old assembly and we will check it. The full range of hard parts for this unit is on the 4L80E collection page.
| Fits | 4L80E 1991-2001 |
| Part type | Clutch Module |
| Condition | Remanufactured |
| 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. It is the remanufactured overrun clutch drum assembly with the overdrive sun gear and one-way clutch fitted, the front overdrive section of the 4L80E.
In manual 2 and 1 the overrun clutch applies and holds the overdrive planetary even if the one-way clutch has failed. In Drive the one-way clutch works alone, so a failed one gives no drive.
Mostly heat. Plowing or towing in Drive puts the whole load on the roller clutch, and overheating can melt its plastic cage.
It is listed for 1991-2001. For later units compare the sun gear, splines and bushings with your old part, or send us your VIN and a photo before ordering.
Dexron VI, the current GM service fluid for the 4L80E. Keep an eye on the transmission temperature gauge when working the truck hard.
