Development of Type C-3 Torque Fluid for Heavy-Duty Power Shift Transmissions

The Type C-3 transmission fluid specification has been completed which defines tighter requirements for fluids used in heavy-duty off-highway automatic or power shift transmissions. A laboratory test program was conducted to develop and prove-out the uprated requirements. The C-3 specification now provides for control of the fluid's effect on clutch friction retention and durability. A redefined oxidation stability test has been included which calls for the use of test hardware that is more readily available. Seal-swell requirements were expanded to include the latest materials used in transmission seals. The cooperative efforts of the petroleum and additive industries, along with Detroit Diesel Allison, are now providing an improved fluid for use in the latest off-highway heavy-duty transmissions.