TH400 Clutch Drum, remanufactured and ready to install. Fits the TH400. Ships fast from the USA.
A TH400 that pulls fine in first and second but flares or slips into third, has weak or no Reverse, or keeps burning up the same clutch pack after a rebuild often has a drum problem, not just a friction problem. This listing is a remanufactured TH400 clutch drum. The housing in the photo is bare and freshly machined, with a smooth outer band surface and a stepped center hub, which is the layout of the TH400 direct clutch housing that the front band wraps around. Compare it with the drum you are replacing before you order.
The TH400 uses three multiple-disc clutches, two one-way clutches and two bands. The direct clutch housing holds the direct clutch piston, its release springs and the five composition and steel plates, and it carries the intermediate one-way clutch (a roller clutch in GM's 1975 manual, a sprag in other years) on its hub. The direct clutch applies in third gear and in Reverse, and in manual second the front band clamps the outside of this same housing for engine braking. So one drum has to seal apply oil through its center, take the clutch plate lugs on its inner splines, and give the band a true, unscored surface. A crack, worn lug slots, a leaking piston bore or a scored band surface each show up as slipping in the gears it serves.
Sonnax notes that on hard-launched TH400s the low roller clutch can let go under high torque, which then takes out the direct drum, so a drum that failed in a high-horsepower unit deserves a look at the low roller clutch too.
Start with a line pressure test, because a weak pump starves every clutch and looks like a bad drum. If pressure is good in Drive but Reverse and third both slip, the direct circuit is suspect. On the bench, air-check the direct piston through the case passage, inspect the housing for cracks around the lug slots and hub, and check the check ball. Our TH400 common problems guide covers the direct drum and low roller failure in detail, and the TH400 pump failure guide explains how to rule out the pump first.
This drum fits the TH400 (also called the 3L80) used across GM trucks, vans, motorhomes and performance and luxury cars from the mid-1960s on. The listing does not name a year range, and GM changed direct housings over the years, including the switch from a check ball in the piston to a check ball in the housing. Match the hub height, the bushing bore, the intermediate one-way clutch type and the lug count against your old drum, or send us your year, vehicle and VIN and we will check it. Year-specific drums such as the TH400 clutch drum for 1964-1990 and every other part for the unit are on the TH400 parts page.
Install the drum with fresh frictions, steels and seals from the TH400 master rebuild kit for 1965-98, and firm up the 2-3 shift with the TH400 shift improver kit.
| Fits | TH400 |
| Part type | Clutch Drum |
| Condition | Remanufactured |
| 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.
The drum in the photo has no turbine shaft and has a smooth outer band surface, which matches the TH400 direct clutch housing. The forward drum has the turbine shaft attached. Compare it with the drum you are replacing, or send us your year and VIN to confirm.
Third gear and Reverse. The front band also holds this housing in manual second for engine braking, so a damaged drum can show up as slipping in third, weak Reverse or no engine braking in L2.
No, this is the drum housing. Install it with new frictions, steels and seals from a TH400 rebuild kit.
GM requires a check ball in either the housing or the piston. If neither has one, use the service direct clutch piston, which has a check ball.
The direct drum design is shared across TH400 applications, but GM revised parts over the years. Match hub height, bushing bore and lug count with your old drum, or send us the year and VIN.
