Dodge Durango

 Service Manual

Transmission and Transfer Case » Diagnosis and testing
Air testing transmission clutch and band operation

Air-pressure testing can be used to check transmission front/rear clutch and band operation. The test can be conducted with the transmission either in the vehicle or on the work bench, as a final check, after overhaul.

Air-pressure testing requires that the oil pan and valve body be removed from the transmission. The servo and clutch apply passages are shown (Fig. 67).

Fig. 67 Air Pressure Test Passages

1 - REAR SERVO APPLY

2 - FRONT SERVO APPLY

3 - PUMP SUCTION

4 - FRONT CLUTCH APPLY

5 - FRONT SERVO RELEASE

6 - LINE PRESSURE TO ACCUMULATOR

7 - PUMP PRESSURE

8 - TO CONVERTER

9 - REAR CLUTCH APPLY

10 - FROM CONVERTER

11 - TO COOLER

Front Clutch Air Test

Place one or two fingers on the clutch housing and apply air pressure through front clutch apply passage.

Piston movement can be felt and a soft thump heard as the clutch applies.

Rear Clutch Air Test

Place one or two fingers on the clutch housing and apply air pressure through rear clutch apply passage.

Piston movement can be felt and a soft thump heard as the clutch applies.

Front Servo Apply Air Test

Apply air pressure to the front servo apply passage.

The servo rod should extend and cause the band to tighten around the drum. Spring pressure should release the servo when air pressure is removed.

Rear Servo Air Test

Apply air pressure to the rear servo apply passage.

The servo rod should extend and cause the band to tighten around the drum. Spring pressure should release the servo when air pressure is removed.

Automatic transmission diagnosis

Effects of incorrect fluid level

Causes of burnt fluid

Fluid contamination

Preliminary diagnosis

Park/neutral position switch

Overdrive electrical controls

Gearshift cable

Road testing

Analyzing road test

Hydraulic pressure test

Air testing transmission clutch and band operation

Converter housing fluid leak diagnosis

Diagnosis tables and charts-re transmission