THM200-4R[edit]

For the 1981 model year, the 200-4R (sometimes called 200R4) was introduced. The components which were prone to failure in the THM200 were improved, and this transmission was used with high-power applications — primarily the Buick Grand National. The 200-4R was configured with several different torque converters and gear ratios depending on the vehicle application.

Unlike the 700R4, most 200-4Rs have a multicase bellhousing for use with Chevrolet, Buick/Olds/Pontiac (BOP), and Cadillac engines. However, 200-4Rs share mounting locations with the TH-400. Since the external dimensions are similar to the TH-350 (overall length, drive shaft yoke spline count/diameter and general size), 200-4Rs are often swapped in place of TH-350s in older vehicles to provide an overdrive gear.

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 THM200-4R can be found in the following vehicles:

• 1981-90 B-Bodies
• 1981-84 C-Bodies
• 1984-88 G-Bodies
• 1985-90 D-Bodies
• 1981 Pontiac Firebird (with 301cid engine, non-turbo)
• 1989 Pontiac Firebird Trans Am Indy Pace car (with Buick V6 and a Turbocharger)

The THM200-4R was phased out after 1990; its final usage was in the GM B-body vehicles.