RAM 2500 Truck 2WD V8-5.7L (2008)
Stator Operation
TORQUE CONVERTER CLUTCH (TCC)
In a standard torque converter, the impeller and turbine are rotating at about the same speed and the stator is freewheeling, providing no torque
multiplication. By applying the turbine's piston and friction material to the front cover, a total converter engagement can be obtained. The result of this
engagement is a direct 1:1 mechanical link between the engine and the transmission.
The clutch can be engaged in second, third, fourth, and fifth (if applicable) gear ranges depending on overdrive control switch position. If the overdrive
control switch is in the normal ON position, the clutch will engage after the shift to fourth gear. If the control switch is in the OFF position, the clutch
will engage after the shift to third gear.
The TCM controls the torque converter clutch via the L/R-CC Solenoid. There are four TCC operational modes:
-
No EMCC
-
Partial EMCC
-
Full EMCC
-
Gradual-to-no EMCC
NO EMCC
Under No EMCC conditions, the L/R Solenoid is OFF. There are several conditions that can result in NO EMCC operations. No EMCC can be initiated
due to a fault in the transmission or because the TCM does not see the need for EMCC under current driving conditions.
PARTIAL EMCC
Partial EMCC operation modulates the L/R Solenoid (duty cycle) to obtain partial torque converter clutch application. Partial EMCC operation is
maintained until Full EMCC is called for and actuated. During Partial EMCC some slip does occur. Partial EMCC will usually occur at low speeds, low
load and light throttle situations.
FULL EMCC
During Full EMCC operation, the TCM increases the L/R Solenoid duty cycle to full ON after Partial EMCC control brings the engine speed within the
desired slip range of transmission input speed relative to engine rpm.
GRADUAL-TO-NO EMCC
This operation is to soften the change from Full or Partial EMCC to No EMCC. This is done at mid-throttle by slowly decreasing the L/R Solenoid duty
cycle.
