4L85E Clutch Module 1991, new and ready to install. Fits the 4L85E. Ships fast from the USA.
When an older heavy-duty GM truck slips in one gear but drives fine in the others, the trouble is usually inside a single clutch assembly rather than the whole transmission. This is a new ACDelco clutch module listed for 1991, the first year of the 4L80E design that the 4L85E was later built on. The photo shows it as a GM service part, boxed and sealed in plastic. It suits owners and rebuilders keeping an early three-quarter or one-ton Chevrolet or GMC pickup, Suburban or full-size van on the road who want a new factory-source part instead of a used core.
This family holds its gears with five multi-plate clutches (overrun, forward, direct, intermediate and fourth) plus two bands and one-way clutches. Each clutch is an assembly: a housing or drum, a piston, return springs, and alternating friction and steel plates. Oil fed through the drum pushes the piston, the plates clamp, and that member is locked. The jobs overlap, so one bad assembly shows up in more than one place. Sonnax notes that Reverse uses the direct clutch, which is also applied in 3rd and 4th, and that the overrun clutch only applies in the manual ranges while the overdrive roller clutch holds alone in Drive. Knowing which gears slip tells you which assembly to replace.
Write down exactly which ranges slip and match them to the clutch application chart in our 4L85E and 4L80E common problems guide. With the unit apart, air-check the circuit and measure the drum. Sonnax's reverse drum wear case is a good warning: a drum that looked fine was worn undersize from heavy duty use, and only pressure testing found it. If the slip is in 3rd and 4th, also read our 3-4 clutch failure guide before replacing parts.
This module is listed for 1991. The 4L85E name came later; 1991 parts belong to the original non-center-lube 4L80E layout, and GM changed the lube routing and several hard parts in 1997. A clutch module is specific to one clutch position, so match the GM part number printed on the box label to the assembly you are replacing, or send us your year, VIN and the case ID tag and we will confirm it before it ships. Other early-year modules, such as the 1990-1996 clutch module, and the rest of the parts for this family are on the 4L85E collection page.
| Fits | 4L85E 1991 |
| Part type | Clutch Module |
| Condition | New |
| Brand | ACDelco |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
No. GM introduced the 4L80E in 1991 and the heavier 4L85E came later on the same design. This module is for the early 4L80E-family layout.
Each module is specific to one clutch position. Match the GM part number on the box label to your old assembly, or send your year, VIN and case tag and we will confirm before shipping.
Do not assume so. GM changed the lube routing and several hard parts in 1997, so check the part number or ask us first.
The piston seals and sealing rings for that assembly, the filter, and any worn bushings. If the pan had a lot of debris, plan a full overhaul.
Dexron VI ATF. Check the level hot in Park after the first drive.
