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200-4R Transmission Spotlight

200-4R Transmission

For the 1981 model year of General Motors vehicles, the 200-4R transmission was introduced in 1980. The 200-4R is the lesser known of the two overdrive transmissions made by General Motors in the 1980’s, but they are still considered part of the Turbo-Hydramatic series that began in the 1930’s.The components were prone to failure in the earlier TH200 model and were improved in the later 1980’s with this line of transmissions. The 200-4R transmission was used with high-power applications, especially the Buick Grand National and the 1989 Pontiac Firebird Trans Am Indy 500 Pace cars. The TH200-4R was configured with several different torque converters and gear ratios, depending on the vehicle application. Many of the vehicles out there that still exceed 700 horsepower are still using the TH200-4R transmission to this day.

Unlike the 700R4, most 200-4Rs have a multi-case bell housing for use with Chevrolet, Buick, Oldsmobile, Pontiac, and Cadillac engines, but the 200-4R shares mounting placement with the TH-400 transmission. Since the outside dimensions are close to the TH-350 transmission, 200-4Rs are often swapped in place of TH-350’s in older vehicles to provide an overdrive gear.

The external dimensions are similar to the Turbo 350 so it is often swapped in older vehicles to provide an overdrive gear. In addition, it has a multicase bell housing for use with Chevrolet, Buick, Oldsmobile, Pontiac, and Cadillac power plants, although the TH200-4R was phased out after 1990. Early models had PRND321 on the cluster, while later models had PRN(D)D21, with the left D identified as the overdrive gear by a square or oval ring.

The TH200-4R transmission, like the TH-350, uses a 27-spline output shaft, which is similar in length to the TH-350 and the TH-200 models, making it a top selection for many overdrive conversions. The TH200-4R transmission is also similar in length to the Powerglide and the Pontiac Super-Turbine 300, which makes it a popular model for converting from a two-speed to a four-speed automatic.

The TH200-4R transmission has a 2.74:1 first gear ratio, with overdrive being 0.67:1. It has an oddly-shaped 16-bolt pan with 13mm bolt heads. The TH200-4R was primarily used in GM rear wheel drive cars that were equipped with the 231 Buick, 301 Pontiac, and the Oldsmobile 307, 350 gas and diesel engines between 1981 and 1990. Many Chevrolet 267 and 305 V-8 engines also came with the TH200-4R transmission because of the multi-fit bell housing. You can still find a TH200-4R transmission in any of these cars:

  • 1981-’90 Cadillac Fleetwood, Deville and Brougham
  • 1981-’88 Buick LeSabre, Electra RWD, Chevelle, Monte Carlo, Malibu & El Camino
  • 1982-’90 Chevrolet Impala, Caprice, Olds Delta 88, 98 & Custom Cruiser
  • 1984-’87 GMC Caballero & Pontiac Grand Prix
  • 1983-’88 Olds Cutlass 442 & Supreme
  • 1983-’89 Pontiac Bonneville, Parisienne & Safari Wagon
  • 1981-’87 Buick Regal
  • 1981 Buick Century & Pontiac Firebird 301

The best TH200-4R transmissions to mount in your vehicle, if you’re looking for performance-grade parts, are typically the units manufactured for the Buick Grand National, Oldsmobile 4-4-2 and Chevrolet Monte Carlo SS during 1986-’87 because this model used a special valve body, a larger reverse boost valve, second to third intermediate servo, and a specially manufactured governor assembly.