ZF/Chrysler Eight Speed RWD: Part 1

ZF/Chrysler Eight Speed RWD Automatic Transmissions
(Completely new modular design unit to accommodate a variety of applications)
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The ZF8HP family of transmissions has only five clutch packs like 6HP, however, they contain four planet sets, all simple gear type. The layout of the unit is compact. There are several different models of the 8HP, depending capacity. They initially ranged from the 8HP30 to the 8HP90 for GEN 1. There are now more models for GEN 2 & 3. Beginning in 2012, Chrysler added the line. Initially, Chrysler purchased the 8HP45 from ZF but in 2013 started to manufacture their own version of the design called the 845RE.

The 8HP is a one-piece case modular design. The transmission uses ASIS (adaptive shift strategy) to enable the TCM to adjust operation throughout the life cycle. An adaptive learn procedure can be performed if issues exist. The procedure will monitor clutch fill time, fill count & fill pressure. Fail safe will default to 6th gear.

To limit drag, three of the five shift components are always applied. Torque converter lock up strategy has also been improved to enhance performance and fuel economy. Certain models have start-stop.

The transmission is drive by wire with a solenoid operated park mechanism. If power is lost, park will have to be released manually.

The valve body is Internally controlled (mechatronic) w/TCM. It contains nine solenoids (two for park).
The pump is a Chain driven remote access vane type with splined converter drive gear & aluminum cover / housing.

Видео ZF/Chrysler Eight Speed RWD: Part 1 канала Transmission Digest