GM Corsica/Beretta 1988-1996 Repair Guide



All of the Corsica/Beretta cars use the Turbo Hydra-Matic 125C automatic transaxle as optional equipment. This is a fully automatic unit of conventional design, incorporating a four element hydraulic torque converter, a compound planetary gear set, and a dual sprocket and drive link assembly. The sprockets and drive link (Hy-Vo chain) connect the torque converter assembly to the transmission gears. The transaxle also incorporates the differential assembly, which is of conventional design. Power is transmitted from the transmission to the final drive and differential assembly through helical cut gears.

By September 1, 1991, Hydra-Matic will have changed the name designation of the THM 125C automatic transaxle. The new name designation for this transaxle will be Hydra-Matic 3T40. Transaxles built between 1989 and 1990 will serve as transitional years in which a dual system, made up of the old designation and the new designation will be in effect. In 1994, the Hydra-Matic 4T60-E automatic transaxle was introduced, in addition to the 3T40 already in use.

No overhaul procedures are given in this guide because of the complexity of the transaxle. Transaxle removal and installation, adjustment, and halfshaft removal, installation, and overhaul procedures are covered.