Description And Operation; Aw-4 Automatic Transmission - Jeep cherokee 2000 Service Manual

21 - 218 AW–4 AUTOMATIC TRANSMISSION

DESCRIPTION AND OPERATION

AW–4 AUTOMATIC TRANSMISSION
DESCRIPTION
The AW–4 is a 4–speed, electronically controlled
automatic transmission (Fig. 1).
The running gear consists of an oil pump, plane-
tary gear sets, clutch and brake units, hydraulic
accumulators, a valve body with electrical solenoids,
and a transmission control module (TCM). Cables are
used to provide shift and throttle pressure control
information. A park/neutral position switch permits
engine starting in the Park and Neutral ranges only.
TRANSMISSION IDENTIFICATION
The transmission I. D. plate is attached to the case
(Fig. 2). The plate contains the transmission serial
and model numbers. Refer to the information on this
plate when ordering service parts.
ELECTRONIC CONTROLS
The AW–4 is electronically controlled in 1, 2, 3 and
D ranges. Controls consist of the transmission control
module (TCM), valve body solenoids and various sen-
sors. The sensors monitor vehicle speed, throttle
opening, shift lever position and brake pedal applica-
tion.
TRANSMISSION GEAR RATIOS
Fourth gear is an 0.75:1 ratio overdrive range.
First, second, third and reverse gear are conventional
ranges. Third gear ratio is 1:1. A separate planetary
gear set provides overdrive operation in fourth gear.
1 – TRANSMISSION I. D. PLATE
OPERATION
GEARTRAIN OPERATION AND APPLICATION CHARTS
fourth and reverse gear elements are outlined in the
function and application charts.
function of various geartrain elements. The Compo-
nent Application Chart indicates which elements
(including valve body solenoids), are applied in the
various gear ranges.
Fig. 1 AW–4 Automatic Transmission
Fig. 2 Transmission Identification
Operation and application of the first through
The Component Function Chart describes basic
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