System Overview - TorqShift(R)6

System Overview

This transmission is a 6-speed electronically controlled transmission which uses planetary gears. Gear selection is achieved by the electronic control of transmission fluid flow to operate various internal clutches.

This transmission includes:

- Torque converter with an integral converter clutch
- Electronic shift and pressure controls
- Single planetary gearset
- Double (ravigneaux) planetary gearset
- Two multi-disc holding clutches
- Three multi-plate drive clutches
- One one way holding clutch
- Main control valve body unit

The main control consists of a valve body assembly with solenoids inside the transmission and is controlled by a PCM for gas engine applications and a Transmission Control Module (TCM) for diesel engine applications. The PCM or TCM operates the electrical components to provide refined engagement feel, shift feel, and shift scheduling.

Engine power reaches the transmission by a torque converter with an integral clutch. The 6 forward gears and one reverse gear are obtained from 2 planetary gearsets.

This automatic transmission is a 6-speed electronically controlled transmission with a main control valve body unit with 7 solenoids and a torque converter. Gear selection is achieved by the control of transmission fluid to operate various internal clutches. The PCM or TCM operates the electrical components and provides control of gear selection, shift pressure and torque converter slip.

In the event of a system fault, the PCM or TCM also provides for Failure Mode Effect Management to maintain maximum functional operation of the transmission with a minimum power reduction. In the event of a total loss of control or electrical power, the basic transmission functions P, R, N and D are retained. Also 5th gear is retained by the hydraulic system.

Identification Tags

Identification Tag Location









Transmission Identification Tag









When servicing the transmission, use the transmission identification tag located on the left side of the transmission case.

Original Solenoid Body Tag









The solenoid body strategy is a file programmed into the PCM or TCM to control the shift, Line Pressure Control (LPC) and TCC solenoids to improve shift quality. The solenoid body tag on the transmission case contains the 13-digit solenoid body strategy and the 8-digit solenoid body identification.

Replacement Solenoid Body Tag









Anytime a new main control is installed, a new solenoid body strategy file is downloaded into the PCM or TCM using the scan tool. A replacement solenoid body tag is supplied with the new solenoid body which contains the 13-digit solenoid body strategy and the 8-digit solenoid body identification. The new tag is placed over the original solenoid body tag.

Solenoid Body Identification and Strategy









If the solenoid body strategy printed on the tag on the solenoid body does not match the solenoid body tag on the side of the transmission case, a new main control must be installed and the solenoid body strategy must be downloaded into the PCM or TCM or harsh shifts will result.

Solenoid Band Number





The solenoids are calibrated from the factory and are not all the same. There are 2 types of solenoids, normally high and normally low solenoids. The solenoids can be replaced separately, but only with the same type of solenoid. The replacement solenoid band number must match the band number of the solenoid being replaced. The band number is printed on the side of the solenoid and will be a 2, 3, 4 or 5.

Gear Availability