700R4 Input Drum 1982-1987, remanufactured and ready to install. Fits the 700R4. Ships fast from the USA.
Rebuilding an early 700R4 out of a 1982-1986 C10 or K10, a square-body Suburban or Blazer, a third-gen Camaro, a C4 Corvette or an S10, and the reverse input drum is cracked, worn or burnt? This is the early-design drum built for those units. It is a remanufactured reverse input drum with its check ball for the 1982 through early 1987 THM 700-R4, before GM changed the drum alongside the auxiliary valve body.
The reverse input drum sits right behind the pump. In Reverse, fluid enters the drum, the piston applies the reverse input clutch, and the drum drives the sun shell so the gearset turns the output backward. The outer surface of the drum is also where the 2-4 band clamps in 2nd and 4th gear, so the drum matters in three of the five ranges. The check ball in the drum lets oil exhaust from behind the piston when the clutch releases, so the clutch does not drag.
The 1982-1986 drum feeds Reverse through a large rectangular hole. When GM added the auxiliary valve body in 1987, it switched to a drum with a small round feed hole of about .095 in. that meters the reverse apply. That is why years matter here: this early-style drum belongs in early non-auxiliary valve body units. Installed in a 1987-1992 unit with the auxiliary valve body, the bigger feed hole applies the reverse clutch too fast and Reverse engages harshly.
Start with fluid level and a pressure gauge. Low line pressure from a loose or misadjusted TV cable kills bands and clutches, and our TV cable and line pressure guide walks through the setting. A weak pump also shows up as poor engagement in every range; see 700R4 pump failure symptoms. With the unit apart, compare the feed hole on your old drum and confirm the check ball moves freely and seats.
Listed for the 1982 through early 1987 700R4, including 1982-1986 Chevrolet and GMC C/K 10-30 pickups and Suburbans and K5 Blazer, 1987 R/V trucks, 1983-1987 S10, S15 and Jimmy, 1985-1987 Astro and Safari, 1983-1987 G-series vans, 1982-1987 Corvette, Caprice, Monte Carlo and El Camino, 1983-1987 Camaro and Firebird, and several Buick, Oldsmobile and Pontiac cars. Because 1987 was a split year, check whether your unit has the auxiliary valve body before ordering. Send us your year and VIN if you are not sure, and see the full 700R4 parts page for other years, including the 1987-1992 input drum.
| Fits | 700R4 1982-1987 |
| Part type | Input 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.
It is the early design for 1982 through early 1987 units without the auxiliary valve body. Late 1987-1992 units use a drum with a smaller round feed hole.
Reverse will likely engage harshly. The 1987-1992 units meter reverse apply through a small round feed hole in the drum, and this early drum has the larger rectangular hole.
Yes. The drum is listed with its check ball, which exhausts oil from behind the piston so the reverse clutch releases cleanly.
The 2-4 band, the reverse clutch frictions and steels, and the piston seals. Check the sun shell and stator shaft rings at the same time.
Look on top of the main valve body under the pan for a small separate valve body bolted to it. Or send us your year and VIN.
