General
The GM 5L40-E transmission is an electrically controlled, five speed unit and is mated with the Td6 diesel engine. The transmission is controlled by an Electronic Automatic Transmission (EAT) ECU which contains software to provide operation as a semi-automatic 'Steptronic' transmission. This allows the transmission to be operated as a conventional automatic unit by selecting P, R, N, or D on the selector lever. Movement of the selector lever across the gate to the 'M/S' position puts the transmission into electronic sport mode.
Movement of the selector lever in a lateral position to the + or - positions puts the transmission into electronic manual 'Steptronic' mode.
Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fuse 53 and fuse 54 of the passenger compartment fuse box (C0632) and the fuse holder (C1875) on R wires. The 100A fuse located in the fuse holder (C1878) provides a constant battery feed to the Engine Control Module (ECM) relay (C1895) on an R wire. The 50A fuse located in the fuse holder (C1876) provides a constant battery feed to the transfer box ECU (C1855) on a pair of R wires.
Fuse 54 of the passenger compartment fuse box (C0583) provides a constant battery feed to the EAT ECU (C0932) on a RY wire. Fuse 53 of the passenger compartment fuse box (C0583) provides a constant battery feed to the ignition switch (C0099) on an R wire. When the ignition switch is turned to the 'auxiliary' position, current flows across the switch (C0099) to fuse 37 of the passenger compartment fuse box (C0585) on a PB wire. Fuse 37 (C0587) provides an ignition feed to the transfer box ECU (C1319) on a PU wire.
When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0099) to fuse 5, fuse 33, and fuse 35 of the passenger compartment fuse box (C0585) on a G wire. Fuse 5 (C0587) provides an ignition feed to the EAT ECU (C0932) on a GW wire. Fuse 33 (C0587) provides an ignition feed to the transfer box ECU (C1319) on a GP wire. Fuse 35 (C0587) provides an ignition feed to the Hill Descent Control (HDC) switch (C0365) on a GBY wire.