PISTON 1S2268 - Caterpillar

The controls for the TH48-E80 Petroleum Transmission and the operation of the TH48-E80 Petroleum Transmission will vary between the different Original Equipment Manufacturers (OEM). Refer to the "Owners Manual" of the OEM for detailed description of the controls and for detailed operating procedures of the TH48-E80 Petroleum Transmission. All shifts are manually requested through the transmission shift controller (switch to ground selector or J1939 CAN shifter)Shifting
Any Forward Gear to Neutral
The transmission will shift directly to neutral from any forward gear.Forward Gear Downshifts
Skip shift commands are allowed, but the transmission will shift sequentially as fast as possible until the desired gear is obtained. If a lower desired gear is input, the transmission will shift directly to that gear.Forward Gear Upshifts
Skip shift commands are allowed, but the transmission will shift sequentially as fast as possible until the desired gear is obtained. All upshifts between forward gears are subject to the upshift inhibit logic. Upshift inhibit logic is intended to both protect transmission durability and to avoid shifts into ranges which would exceed available engine torque.If an upshift is commanded, the load factor is calculated to determine if a shift to the desired gear is allowed. If the shift is allowed, the transmission will upshift directly from the current to the desired gear. If the shift is not allowed, the shift control logic will remain in this state until an acceptable gear transition is input to the controller or the engine load decreases. If the desired gear input is changed before the actual gear reaches the original new desired gear, the following will occur: the process will be amended and continue on to the new desired gear if load factors are honored. If the new desired shift is not allowed, the shift sequence will continue on to the original new desired gear. A shift sequence can only be interrupted by a call to a new desired gear with an acceptable load factor.To make the strategy independent of the engine type, the strategy is designed to use J1939 engine broadcast torque. The engine broadcast torque is calculated in n*m with the following: engine reference torque, actual engine percent torque and nominal engine friction percent torque. If the necessary J1939 CAN messages are present to execute the broadcast torque based upshift inhibit, the transmission ECM will use this method. For engines which do not broadcast reference torque on CAN, the reference torque must be entered in Cat ET. The ECM will only use the reference torque which is entered in Cat ET if the engine broadcast reference torque is unavailable.For engines such as the 3512B which do not support the broadcasting of these messages, the following will occur: the transmission software will default to using EEC2 percent load at current speed to obtain similar upshift inhibit functionality. Since this parameter can vary from engine to engine, absolute broadcast torque in n*m is preferred. Using EEC2 percent load at current speed can also cause the following: unwanted shift inhibits in the overrun portion of