Talk:General Motors transmissions

The TH200 was introduced during the 1976 model year - also the first GM transmission with metric fasteners. As with the TH350/400, its a 3 speed transmission, with 1979-87 production models using lockup torque converters. TH200s have a one-piece case design which resembles a Powerglide without a bolt on tailhousing - the passenger side has the intermediate servo cover which resembles the 2-4 servo used with the THM700R4/4L60E. TH200s also lack a vacuum modulator where a throttle valve cable is used to control shift points (similar to the Chrysler Torqueflite, TH2004R, and THM700R4/4L60). Unlike the later GM overdrives, TH200s have a cast iron pump. TH200 (including the TH200C) have the following bellhousing patterns - Chevrolet V8/inline six/90 degree V6, BOP V8 and V6, Vega/Monza Durabuilt 140, Isuzu 4 cylinder used with the GM T platform (Chevette incl. the Buick/Opel by Isuzu (rebadged Isuzu Gemini) and Chevrolet LUV), and the 2.8 bolt pattern (used with the early production Chevrolet S10/GMC S-15s with a 4 cylinder (incl Tech IV) or 2.8L). Although considered a light duty transmission, when used with some heavier vehicles e.g. GM B or G-bodies, this has resulted in a high failure rate where its common for the TH200 to be swapped out with a TH350. Although not intended for heavy duty usage, the TH200 has been used as Powerglide substitute where Scott McClay Engineering has improved the TH200's weak points by using some TH2004R internals.  

TH200-4R was introduced in 1981 which uses some internals from the TH200/200C eg. low/reverse planetaries, reaction carrier, low/reverse sprag) along with improved hard parts which has plagued the original TH200 design - oil pump design uses pump vanes in lieu of pump gears (this design is shared with the 700R4/4L60E). As a result of the redesigned one piece case resembling a scaled down TH400 to accommodate the overdrive assembly, the transmission mount is located in the same location as a short tailhousing TH400.