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21 - 40 TRANSAXLE

FLUID LEVEL AND CONDITION

The transmission and differential sump have a common oil sump with a communicating opening between the two.

Before removing the dipstick, wipe all dirt off of the protective disc and the dipstick handle.

The torque converter will fill in both the P Park or N Neutral positions. Place the selector lever in P Park to check fluid level.

Inspect fluid level on dipstick every six months.

Allow the engine to idle for at least one minute with vehicle on level ground. This will assure complete oil level stabilization between differential and transmission. A properly filled transaxle will read near the add mark when fluid temperature is 21 degrees Celsius (70 degrees Fahrenheit). When the transaxle reaches operating temperature the fluid should be in the HOT region.

Low fluid level can cause a variety of conditions because it allows the pump to take in air along with the fluid. As in any hydraulic system,

air bubbles make the fluid spongy, therefore, pressures will be low and build up slowly.

Improper filling can also raise the fluid level too high. When the transaxle has too much fluid, the gears churn up foam and cause the same

conditions which occur with a low fluid level.

In either case, the air bubbles can cause overheating, fluid oxidation, and varnishing, which can interfere with normal valve, clutch, and servo operation. Foaming can also result in fluid escaping from the transaxle vent (dipstick handle) where it may be mistaken for a leak.

Along with fluid level, it is important to check the condition of the fluid. When the fluid smells burned, and is contaminated with metal or friction material particles, a complete transaxle overhaul is needed. Be sure to examine the fluid on the dipstick closely. If there is any doubt about its condition, drain out a sample for a double check.

After the fluid has been checked, seat the dipstick fully to seal out water and dirt.

SELECTION OF LUBRICANT

It is important that the proper lubricant be used in these transmissions. MOPARt ATF PLUS (Automatic Transmission Fluid-Type 7176) should be used to aid in assuring optimum transmission performance. Fluids of the type labeled DEXRON II Automatic Transmission Fluid should be used only if the recommended fluid is not available. It is important that the transmission fluid be maintained at the prescribed level using the recommended fluids.

SPECIAL ADDITIVES

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ception to this policy is the use of special dyes to aid in detecting fluid leaks. The use of transmission sealers should be avoided, since they may adversely affect seals.

FLUID AND FILTER CHANGE

When the factory fill fluid is changed, only fluids of the type labeled MOPARt ATF PLUS

(Automatic Transmission fluid) Type 7176 should be used. A band adjustment and filter change should be made at the time of the oil change. The magnet (on the inside of the oil pan) should also be cleaned with a clean, dry cloth.

If the transaxle is disassembled for any reason, the fluid and filter should be changed, and the band(s) adjusted.

FLUID DRAIN AND REFILL

(1)Raise vehicle on a hoist (See Lubrication, Group 0). Place a drain container with a large opening, under transaxle oil pan.

(2)Loosen pan bolts and tap the pan at one corner to break it loose allowing fluid to drain, then remove the oil pan.

(3)Install a new filter and gasket on bottom of the valve body and tighten retaining screws to 5 NIm (40 in. lbs.).

(4)Clean the oil pan and magnet. Reinstall pan

using new MOPARt Adhesive sealant. Tighten oil pan bolts to 19 NIm (165 in. lbs.).

(5)Pour four quarts of MOPARt ATF PLUS (Automatic Transmission Fluid) Type 7176 through the dipstick opening.

(6)Start engine and allow to idle for at least one minute. Then, with parking and service brakes applied, move selector lever momentarily to each position, ending in the park or neutral position.

(7)Add sufficient fluid to bring level to 1/8 inch below the ADD mark.

Recheck fluid level after transaxle is at normal operating temperature. The level should be in the HOT region (Fig. 1).

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To prevent dirt from entering transaxle, make certain that dipstick is full seated into the dipstick opening.

LOCKUP SOLENOID WIRING CONNECTOR

If wiring connector is unplugged, the torque converter will not lock-up (Fig. 1).

Fig. 1 Lockup Solenoid Wiring Connector

ROAD TEST

Prior to performing a road test, be certain that the fluid level and condition, and control cable adjustments have been checked and approved.

During the road test, the transaxle should be operated in each position to check for slipping and any variation in shifting.

If vehicle operates properly at highway speeds, but has poor acceleration, the torque converter stator overrunning clutch may be slipping. If through-gear acceleration is normal, but high throttle opening is required to maintain highway speeds, the torque converter stator clutch may have seized. Both of these stator defects require replacement of the torque converter.

Observe closely for slipping or engine speed flareup. Slipping or flare-up in any gear usually indicates clutch, band, or overrunning clutch problems. If the

TRANSAXLE 21 - 41

condition is far advanced, an overhaul will probably be necessary to restore normal operation.

The clutch or band that is slipping can be determined by noting the transaxle operation in all selector positions. Then comparing which internal units are applied in those positions. The Elements in Use Chart provides a basis for road test analysis.

The rear clutch is applied in both the D first gear and 1 first gear positions. Also the overrunning clutch is applied in D first gear and the low/reverse band is applied in 1 first gear position. If the transaxle slips in D range first gear, but does not slip in 1 first gear, the overrunning clutch is slipping. Similarly, if the transaxle slips in any two forward gears, the rear clutch is slipping.

Using the same procedure, the rear clutch and front clutch are applied in D third gear. If the transaxle slips in third gear, either the front clutch or the rear clutch is slipping. By selecting another gear which does not use one of those units, the unit which is slipping can be determined. If the transaxle also slips in reverse, the front clutch is slipping. If the transaxle does not slip in reverse, the rear clutch is slipping.

The process of elimination can be used to detect any unit which slips and to confirm proper operation of good units. Road test analysis can usually diagnose slipping units, but the actual cause of the malfunction usually cannot be decided. Practically any condition can be caused by leaking hydraulic circuits or sticking valves.

Unless the condition is obvious, like no drive in D range first gear only. The transaxle should never be disassembled until hydraulic pressure tests have been performed.

HYDRAULIC PRESSURE TESTS

Pressure testing is a very important step in the diagnostic procedure. These tests usually reveal the cause of most transaxle problems.

Before performing pressure tests, be certain that fluid level and condition, and control cable adjustments have been checked and approved.

Fluid must be at operating temperature (150 to 200 degrees F.).

Install an engine tachometer, raise vehicle on hoist which allows front wheels to turn, and position tachometer so it can be read.

Disconnect throttle cable and shift cable from transaxle levers so they can be controlled from outside the vehicle.

Attach 150 psi gauges to ports required for test being conducted. A 300 psi gauge (C-3293) is required for reverse pressure test at rear servo.

Test port locations are shown in (Fig. 2).

TEST ONE (SELECTOR IN 1)

(1)Attach gauges to line and low-reverse ports (Fig. 2).

(2)Operate engine at 1000 rpm for test.

(3)Move selector lever on transaxle all the way rearward (1 position).

(4)Read pressures on both gauges as throttle lever on transaxle is moved from full clockwise position to full counterclockwise position.

(5)Line pressure should read 52 to 58 psi with throttle lever clockwise and gradually increase, as lever is moved counterclockwise, to 80 to 88 psi.

(6)Low-reverse pressure should read the same as line pressure within 3 psi.

(7)This tests pump output, pressure regulation, and condition of rear clutch and rear servo hydraulic circuits.

TEST TWO (SELECTOR IN 2)

(1)Attach one gauge to line pressure port and tee another gauge into lower cooler line fitting. This will allow you to read lubrication pressure (Fig 2).

(2)Operate engine at 1000 rpm for test.

(3)Move selector lever on transaxle one detent forward from full rearward position. This is selector 2 position.

(4)Read pressures on both gauges as throttle lever on transaxle is moved from full clockwise position to full counterclockwise position.

(5)Line pressure should read 52 to 58 psi with throttle lever clockwise and gradually increase, as lever is moved counterclockwise, to 80 to 88 psi.

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(6)Lubrication pressure should be 10 to 25 psi with lever clockwise and 10 to 35 psi with lever full counterclockwise.

(7)This tests pump output, pressure regulation, and condition of rear clutch and lubrication hydraulic circuits.

TEST THREE (SELECTOR IN D)

(1)Attach gauges to line and kickdown release ports (Fig. 2).

(2)Operate engine at 1600 rpm for test.

(3)Move selector lever on transaxle two detents forward from full rearward position. This is selector D position.

(4)Read pressures on both gauges as throttle lever on transaxle is moved from full clockwise position to full counterclockwise position.

(5)Line pressure should read 52 to 58 psi with throttle lever clockwise and gradually increase, as lever is moved counterclockwise to 80 to 88 psi.

(6)Kickdown release is pressurized only in direct drive and should be same as line pressure within 3 psi, up to kickdown point.

(7)This tests pump output, pressure regulation, and condition of rear clutch, front clutch, and hydraulic circuits.

TEST FOUR (SELECTOR IN REVERSE)

(1)Attach 300 psi gauge to low-reverse port (Fig.

2).

(2)Operate engine at 1600 rpm for test.

(3)Move selector lever on transaxle four detents forward from full rearward position. This is selector R position.

(4)Low-reverse pressure should read 180 to 220 psi with throttle lever clockwise and gradually increase, as lever is moved counterclockwise to 260 to 300 psi.

(5)This tests pump output, pressure regulation, and condition of front clutch and rear servo hydraulic circuits.

(6)Move selector lever on transaxle to D position to check that low-reverse pressure drops to zero.

(7)This tests for leakage into rear servo, due to case porosity, which can cause reverse band burn out.

TEST RESULT INDICATIONS

(1)If proper line pressure, minimum to maximum, is found in any one test, the pump and pressure regulator are working properly.

(2)Low pressure in D, 1, and 2 but correct pressure in R indicates rear clutch circuit leakage.

(3)Low pressure in D and R but correct pressure in 1 indicates front clutch circuit leakage.

(4)Low pressure in R and 1 but correct pressure in 2 indicates rear servo circuit leakage.

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(5) Low line pressure in all positions indicates a defective pump, a clogged filter, or a stuck pressure regulator valve.

GOVERNOR PRESSURE

Test only if transaxle shifts at wrong vehicle speeds when throttle cable is correctly adjusted.

(1)Connect a 0-150 psi pressure gauge to governor pressure take-off point, located at lower right side of case, below differential cover (Fig. 2).

(2)Operate transaxle in third gear to read pressures. The governor pressure should respond smoothly to changes in mph and should return to

0 to 3 psi when vehicle is stopped. High pressure at standstill (above 3 psi) will prevent the transaxle from downshifting.

THROTTLE PRESSURE

No gauge port is provided for throttle pressure. Incorrect throttle pressure should only be suspected if part throttle upshift speeds are either delayed or occur too early, with a correctly adjusted throttle cable. Engine runaway on either upshifts or downshifts can also be an indicator of incorrect (low) throttle pressure setting, or misadjusted throttle cable.

In no case should throttle pressure be adjusted until the transaxle throttle cable adjustment has been verified to be correct.

CLUTCH AND SERVO AIR PRESSURE TESTS

A no drive condition might exist even with correct fluid pressure, because of inoperative clutches or bands. The inoperative units, clutches, bands, and servos can be located through a series of tests by substituting air pressure for fluid pressure (Fig. 3).

The front and rear clutches, kickdown servo, and low-reverse servo may be tested by applying air pressure to their respective passages after

the valve body assembly has been removed. To make air pressure tests, proceed as follows:

Compressed air supply must be free of all dirt or moisture. Use a pressure of 30 psi.

Remove oil pan and valve body See DisassemblySubassembly Removal.

FRONT CLUTCH

Apply air pressure to front clutch apply passage and listen for a dull thud which indicates that front clutch is operating. Hold air pressure on for a few seconds and inspect system for excessive oil leaks.

REAR CLUTCH

Apply air pressure to rear clutch apply passage and listen for a dull thud which indicates that rear clutch is operating. Also inspect for excessive oil leaks. If a dull thud cannot be heard in the clutches,