2012/05/02 Caterpillar

On-Highway Transmission:

CX31 (S/N: HTC1-UP; D9F1-UP; D9R1-UP; PTT1-UP; EBW1000-UP; PTW1-UP)

On Highway Truck:

CT660 (S/N: TRK1-UP; TKL1-UP; TGT1-UP; TSW1-UP; TSY1-UP)

The new 393-0461 Power Train Software Gp is available for certain On Highway Trucks and the CT660 that are equipped with the CX31 On-Highway Transmission.

The new transmission software is adaptable to the above serial numbers. The new software for the transmission is available in SIS Web. Download "393-0461.FLS" flash file in order to update the ECM with the latest software.

Note: Do not use this new software on any 15 Liter engine application.

Software Improvements

A number of changes have been made that will be noticed by the operator.

• Lowered transmission requested fan turn on speed to 5F below the amber warning light temperature to maximize cooling efforts.

• Tuning enhancements for the 5 to 4 retarding downshift. The operator will notice the 5 to 4 retarding shift quality will be an improvement over the previous version of software.

• Tuning enhancements for the 3 to 2 retarding downshift. The operator will notice the 3 to 2 retarding shift quality will be an improvement over the previous version of software.

• Removed engine torque reduction during the 2 to 1 shift. The perceived 2 to 1 dead throttle pedal is reduced significantly. Back to back shifts may still trigger a shift inhibit event.

• Updated how much torque is taken away during a powered upshift. The perception is that the vehicle will feel to be constantly accelerating.

• Tuning refinement to accommodate upshift STM changes.

• Coasting lock up clutch engagement enhancements. The operator will notice improved lock up clutch shift quality during coasting upshift engagements.

• Reduced time for First to Reverse and Reverse to First shifts. The perception of being in Neutral during directional shifts is eliminated.