THM425 Transmission parts, repair guidelines, problems, manuals

Transmission general data

Number of gears Transmission Type Drive ATF (full capacity) L ATF (change) L ATF type
3 AT RWD 12,3 6 Dexron II

The THM425 (and later 325) is a 3-speed automatic gearbox designed and released by GM. The structure of the THM425 is based on the THM400; most spare parts in these gearboxes are directly interchangeable and some others can be adjusted with the help of slight modifications. The THM425 was designed for Oldsmobile Toronado and Cadillac Eldorado.

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Overhaul Kit | Friction Kit | Friction | Steel Plate | Steel Kit | Band | Solenoid Kit | Solenoid EPC | Solenoid TCC | Pump | Shaft | Drum | Valve body | Torque converter | Hub | Piston | Piston Kit | Planetary Gear | Filter | Gasket | Bushing | Seal | Bearing | Pressure Plate | Stator | Differential | Retainer | Inhibitor Switch | Instruction manual | TOOLS & ACCESORIES | Sensor

Related transmission models or modifications of this transmission:
Part type Expand

More lightweight gearbox THM325 took the place of the THM425 in both car ranges in late 1978. Since 1979 and later longitudinal engine FWD cars have been equipped with the THM325. The THM325 was upgraded to THM325-4L with an overdrive added in 1982, but all cars with this gearbox switched to more-common transverse engine mounting in 1986.