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3T40 Transmission parts

TH125, TH125C

Transmission general data

Number of gears Transmission Type Drive Torque (Nm) ATF (full capacity) L ATF (change) L ATF type (recommended)
3 AT FWD 250 8,5 3,8 Dexron III

The 3-speed automatic transmission GM 3T40 named as Turbo-Hydramatic 125C was installed on FWD cars with engine capacity from 2 up to 3.1 liters. The first modifications of this transmission did not have the torque converter, later versions (1995) had an electronic control and letter E was added to a new name GM 3T40E. The most significant modification was introduced in 1984. Since then sets of gaskets and seals have not been changed.

What are you looking for?

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

Which cars run with this gearbox? CLICK

Technical issues and repair guidelines

The GM 3T40 is a reliable, simple transmission that operates over 300 thousand kilometers. It served as a prototype for the 4-speed family 4T40E -4T60E.This transmission rarely gets in repair services. The main spare parts ordered for repair of this transmission are the repair kit of gaskets and seals (Overhaul kit) or a complete Masterkit (with clutches and seals).