sion used for such applications. Some of its features include: • Real-time, adaptive, closed loop shift and pressure control. • Electronic shift and torque con- verter clutch controls to help pro- tect the transmission from damage due to high temperatures, which can occur under severe operating conditions. By altering shift schedules, line

pressure, and converter clutch control, these controls reduce heat generation and increase transmission cooling. The 68RFE is somewhat unusual

in its components: To help reduce pres- sure losses, the transmission includes a dual-stage transmission fluid pump with electronic output pressure control. Under most driving conditions, pump output greatly exceeds what’s needed to keep the clutches applied. The 68RFE pressure control sys-

tem monitors input torque and adjusts the pressure accordingly. The primary stage of the pump works continuously; the second stage is bypassed when demand is low. The control system also monitors input and output speeds: If the computer sees the clutches slipping, it adjusts the duty cycle to the pressure control solenoid, increasing pressure in proportion to demand. A high-travel torque converter

damper assembly allows the torque converter clutch to engage sooner, to reduce slip. Needle-type thrust bearings reduce internal friction. The 68RFE is packaged in a one-piece die-cast alu- minum case. To reduce noise and vibra- tion, the case is very stiff in all direc- tions. Dual filters protect the pump and other components. The main sump filter has a cooler return filter added to it. Independent

4

Meet the 68RFE

I

n 2007, Dodge introduced the 68RFE to their truck lines. The 68RFE is a heavy duty transmis-

Figure 1

by The ATRA Technical Department

members.atra.com www.atra.com

Figure 2

Figure 3

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