Dodge Nitro. Manual - part 350

Fig. 272: Identifying Torque Converter Components
Courtesy of CHRYSLER LLC 

The TCC (9) was installed to improve the efficiency of the torque converter that is lost to the slippage of the 
fluid coupling. Although the fluid coupling provides smooth, shock-free power transfer, it is natural for all fluid 
couplings to slip. If the impeller and turbine were mechanically locked together, a zero slippage condition could 
be obtained. A hydraulic piston with friction material was added to the turbine assembly to provide this 
mechanical lock-up. See Fig. 272. 

In order to reduce heat build-up in the transmission and buffer the powertrain against torsional vibrations, the 
TCM can duty cycle the torque converter lock-up solenoid to achieve a smooth application of the torque 
converter clutch. This function, referred to as Electronically Modulated Converter Clutch (EMCC) can occur at 
various times depending on the following variables: 

Shift lever position  

Current gear range  

Transmission fluid temperature  

Engine coolant temperature  

Input speed  

Throttle angle  

Engine speed  

OPERATION 

TORQUE CONVERTER 

1 - TURBINE
2 - IMPELLER
3 - STATOR
4 - INPUT SHAFT
5 - STATOR SHAFT
6 - PISTON
7 - COVER SHELL
8 - INTERNALLY TOOTHED DISC CARRIER
9 - CLUTCH PLATE SET
10 - EXTERNALLY TOOTHED DISC CARRIER
11 - TURBINE DAMPER

 

2007 Dodge Nitro R/T 

2007 AUTOMATIC TRANSMISSION NAG1 - Service Information - Nitro

  

Fig. 273: Cutaway View Of Torque Converter 
Courtesy of CHRYSLER LLC 

1 - TURBINE
2 - IMPELLER
3 - STATOR
4 - INPUT SHAFT
5 - STATOR SHAFT
6 - TURBINE DAMPER

 

2007 Dodge Nitro R/T 

2007 AUTOMATIC TRANSMISSION NAG1 - Service Information - Nitro

  

The converter impeller (driving member) (2), which is integral to the converter housing and bolted to the engine 
drive plate, rotates at engine speed. The converter turbine (driven member) (1), which reacts from fluid pressure 
generated by the impeller, rotates and turns the transmission input shaft (4). See Fig. 273. 

TURBINE 

As the fluid that was put into motion by the impeller blades strikes the blades of the turbine, some of the energy 
and rotational force is transferred into the turbine and the input shaft. This causes both of them (turbine and 
input shaft) to rotate in a clockwise direction following the impeller. As the fluid is leaving the trailing edges of 
the turbine's blades it continues in a "hindering" direction back toward the impeller. If the fluid is not redirected 
before it strikes the impeller, it will strike the impeller in such a direction that it would tend to slow it down. 

STATOR 

Fig. 274: Stator Operation 
Courtesy of CHRYSLER LLC 

1 - DIRECTION STATOR WILL FREE WHEEL DUE TO OIL PUSHING ON BACKSIDE OF 

 

2007 Dodge Nitro R/T 

2007 AUTOMATIC TRANSMISSION NAG1 - Service Information - Nitro

  

Torque multiplication is achieved by locking the stator's over-running clutch to its shaft Under stall conditions 
(the turbine is stationary), the oil leaving the turbine blades strikes the face of the stator blades and tries to rotate 
them in a counterclockwise direction. When this happens the over-running clutch of the stator locks and holds 
the stator from rotating. With the stator locked, the oil strikes the stator blades and is redirected into a "helping" 
direction before it enters the impeller. This circulation of oil from impeller to turbine, turbine to stator, and 
stator to impeller, can produce a maximum torque multiplication of about 2.0:1. As the turbine begins to match 
the speed of the impeller, the fluid that was hitting the stator in such as way as to cause it to lock-up is no longer 
doing so. In this condition of operation, the stator begins to free wheel and the converter acts as a fluid 
coupling. See Fig. 274. 

TORQUE CONVERTER CLUTCH (TCC) 

VANES
2 - FRONT OF ENGINE
3 - INCREASED ANGLE AS OIL STRIKES VANES
4 - DIRECTION STATOR IS LOCKED UP DUE TO OIL PUSHING AGAINST STATOR VANES

 

2007 Dodge Nitro R/T 

2007 AUTOMATIC TRANSMISSION NAG1 - Service Information - Nitro