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AX4N Automatic Transaxle 

Description and Operation | Transaxle Range Selection | Transaxle Shift Patterns
AX4N Transaxle Sectional View

Description and Operation

The AX4N automatic transaxle is a four-speed unit with electronic shift control. It is designed for operation in a transverse powertrain for front-wheel drive vehicles.

The AX4N automatic transaxle has the following major components:

Transaxle Range Selection--3.4L SHO

Vehicles equipped with the AX4N transaxle and a 3.0L (4V) or 3.4L SHO use a transmission control switch (TCS). The shift quadrant has the following positions: P, R, N, D, 2 and 1.

No powerflow is transferred through the transaxle in PARK. A parking pawl actuating rod assembly presses the parking pawl into the park gear on the final drive sun gear. This locks the final drive and prevents the vehicle from rolling. For safety reasons, the parking brake should always be applied whenever the vehicle is parked.

Allows the vehicle to be operated in a rearward direction, at a reduced gear ratio. Engine braking is provided in REVERSE.

As in PARK, there is no power transferred through the transaxle in NEUTRAL. However, the final drive is not locked by the parking pawl assembly, so the wheels are free to rotate. The engine may be started in NEUTRAL.

This position provides all automatic shifts for first through fourth gears. This position also provides apply and release of the torque converter clutch (TCC). Coast braking occurs in third gear.

Fourth (OD) gear can be removed from the shift schedule by depressing the transmission control switch (TCS) on the transaxle range selector lever. Shift schedule status is displayed on the instrument cluster by the transmission control indicator lamp (TCIL) below the tachometer. If the TCIL display reads "O/D OFF", overdrive has been removed from the shift schedule and is not available. Depressing the TCS a second time restores overdrive to the shift schedule.
Manual 2

This position provides second gear start. Application of the torque converter clutch (TCC) may also occur in this range depending on transaxle and vehicle conditions. This position can be selected when starting on slippery roads for improved traction or engine braking.

Manual 1

Provides a first gear hold after automatic or manual downshift. The transaxle is prevented from downshifting into first gear above a specific speed (approximately 48 km/h (30 mph)) to protect the powertrain from over-speeding. Engine braking is provided in 1 position making it especially useful for descending steep grades.

Transaxle Shift Patterns

Under certain conditions the transaxle will downshift automatically to a lower gear range (without moving the transaxle range selector lever). There are three categories of automatic downshifts: coastdown, torque demand, and forced or kickdown shifts.

The coastdown downshift occurs as the name indicates, when the vehicle is coasting down to a stop.
Torque Demand

The torque demand downshift occurs (automatically) during part throttle acceleration when the demand for torque is greater than the engine can provide at that gear ratio. The transaxle will disengage the torque converter clutch to provide added acceleration, if applied.

For maximum acceleration, the driver can force a downshift by pressing the accelerator pedal to the floor. A forced downshift into second gear is possible below 105 km/h (65 mph). Below approximately 48 km/h (30 mph) a forced kickdown to first gear will occur. For all shift speeds, specifications are subject to variation due to tire size and engine calibration requirements.

AX4N Automatic Transaxle--Sectional View
right click, view image, for larter picture

Item Part Number Description
1 7902 Torque Converter
2 -- Forward Clutch Assy 
3 -- Direct Clutch Assy
4 -- Intermediate Clutch Assy
5 -- Reverse Clutch Assy
6 -- Low/Intermediate Clutch Assy
7 7A153 Final Drive Ring Gear
8 -- Final Drive Gearset (Part of 7F465)
9 -- Differential Assy
10 7C190 Low/Intermediate One-Way Roller Clutch Assy 
11 7A162 Coast Band
12 7H281 Coast Servo Piston
13 7D006 Rear Planetary Gearset
14 7A153 Rear Planetary Ring Gear 
15 7A398 Front Planetary Gearset 
16 7G343 Overdrive Band 
17 7D171 Direct One-Way Roller Clutch Assy
18 7A089 Low One-Way Sprag Clutch
19 7G132 Driven Sprocket
20 7G249 Drive Chain 
21 7G129 Drive Sprocket 
22 -- Pump Assy (Part of 7A100) 
23 -- Reactor (Part of 7902) 
24 -- Impeller (Part of 7902)
25 -- Turbine (Part of 7902)

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