Refer to the identification charts in Routine Maintenance for powertrain combinations and identification plate locations and explanations.
On September 1, 1991, Hydra-matic changed the name designations of the THM 125C and THM 440-R4 automatic transaxle. The new name designations are Hydra-matic 3T40 and 4T60. Transaxles built between 1989-1990 served as transitional years in which a dual system, made up of the old designation and the new designation in effect.
The transaxle has an identification tag and stamp on the exterior of the case. The identification information will assist in servicing and ordering parts.