200-4R Clutch Drum 1981-1990, used and ready to install. Fits the 200-4R. Ships fast from the USA.
Rebuilding a 1981-1990 200-4R out of a Buick Grand National, Regal, Monte Carlo, Cutlass or Caprice and found the forward drum cracked, the bore galled, or the sealing ring lands worn into steps? This is a refurbished 200-4R forward clutch drum with its splined shaft, a 4-clutch drum for the 1981-1990 units. It is sold without the check ball. That is deliberate: it is the lower-cost option for a builder who will move the ball over from the old drum or fit a new one, and it is the drum to order when the rest of your forward assembly is good.
Power leaves the converter, passes through the overdrive section at the front of the case, and enters the THM200-style gear train. The forward clutch in this drum is on in every forward gear, from first through overdrive, which is why a failing drum produces a forward-only problem. Reverse bypasses it and uses the direct clutch with the low/reverse clutch. Inside the drum, apply oil comes in through sealing rings on the hub and pushes the piston into the forward pack. A crack anywhere between the feed holes and the piston cavity bleeds that oil away and the pack slips.
A drum is usually confirmed on the bench, not in the driveway. In the car, rule out low fluid, a TV cable out of adjustment, a sticking pressure regulator and a loose valve body; B&M's 200-4R troubleshooting chart lists every one of those as a cause of forward slips and no-move. A line pressure reading in Drive and Reverse tells you whether the pump is doing its job, and our 200-4R pump failure guide covers what low pressure looks and sounds like. Once the unit is out, clean the drum and look at it under good light, then air-check the piston. If you are still sorting out whether the trouble is the forward circuit or a shift problem, read 200-4R valve body symptoms and testing first.
Listed for the 1981-1990 200-4R in GM rear-wheel-drive cars. Because GM revised the 200-4R during its run, lay this drum beside your original and compare the shaft spline count, the 4-clutch friction count, the hub and ring grooves, and the snap ring groove. Send your year and VIN with a photo of your drum if you want us to check before you order. All of our parts for this unit are on the 200-4R parts page. If you would rather receive a drum with the ball already installed, order the 1981-1990 forward drum with check ball instead.
Pair it with a matching 200-4R sun shell if yours shows cracked or worn splines, since both live in the same gear train.
| Fits | 200-4R 1981-1990 |
| Part type | Clutch Drum |
| Condition | Used |
| 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.
It is the bare refurbished drum for builders who will transfer the ball from their old drum or install a new one. If you want a drum with the ball already in it, order the 1981-1990 forward drum with check ball listing.
No. The ball lets oil exhaust from the piston cavity when the forward clutch releases and seals when it applies. Install a ball, confirm it seats, and air-check the clutch before the valve body goes on.
It is listed for the 1981-1990 200-4R. Compare the shaft splines, the 4-clutch friction count, the hub ring grooves and the snap ring groove to your original drum, or send us your year and VIN with a photo to confirm.
Look for cracks near the piston bore and spline base, stepped sealing ring lands and a piston that will not hold air with new seals. A forward pack that burns again soon after a clutch-only rebuild also points at the drum or at low line pressure.
Forward piston seals, hub sealing rings, frictions and steels, usually in a master rebuild kit, plus a check ball if your old one is lost. Inspect the pump and sun shell while the unit is apart.
