Automatic Transmission/Transaxle: Testing and Inspection

HYDRAULIC PRESSURE TEST

Hydraulic test pressures range from a low of one psi (6.895 kPa) governor pressure, to 300 psi (2068.5 kPa) at the rear servo pressure port in reverse.
Use 100 psi Pressure Gauge C-3292 to check pressure at the accumulator, front servo, governor and fluid cooler line. Use 300 psi Gauge C-3293 to check pressure at the rear servo. The 300 psi gauge can be used at any other port when more than one gauge is required for testing.

PRESSURE TEST PORT LOCATIONS






There are pressure test ports at the accumulator, front servo, rear servo and governor. Line pressure is checked at the accumulator port on the right side of the case (Fig. 4). The front servo release pressure port is at the right side of the case just behind the filler tube opening (Fig. 4).






The rear servo pressure port is at the right rear of the transmission ease (Fig. 5).






On 4 x 2 models, the governor pressure port is at the left side of case at the transmission rear (Fig. 5). On 4 x 4 transmissions, the test port is in the driver side of the adapter housing (Fig. 6). Transmission)

PRESSURE TEST PROCEDURE

Connect a tachometer to the engine. Position the tachometer so it can be observed from under the vehicle. Raise the vehicle on hoist that Will allow the wheels to rotate freely.

Test One-Transmission In 1 Range

This test checks pump output, pressure regulation, and condition of the rear clutch and rear servo circuits. Use 300 psi Test Gauge C-3293 for this test
(1) Connect test gauges to line pressure and rear servo ports (Figs. 4-6). Be sure pressure test gauge is connected to rear servo port.
(2) Disconnect throttle and gearshift rods at transmission.
(3) Start and run engine at 1000 rpm.
(4) Move valve body selector lever forward into 1 range.
(5) Read pressures on both gauges as transmission throttle lever is moved from full forward to full rearward position.
(6) Line pressure should be 54-60 psi (372-414 kPa) with throttle lever forward and gradually increase to 90-96 psi (620-662 kPa) as lever is moved rearward.
(7) Rear servo pressure should be same as line pressure within 3 psi.

Test Two-Transmission In 2 Range

This test checks pump output and pressure regulation. Use 100 psi Test Gauge C-3292 for this test.






(1) Connect test gauge to line pressure port (Fig. 4).
(2) Start and run engine at 1000 rpm.
(3) Move valve body selector lever one detent rearward from full forward position. This is 2 range.
(4) Move transmission throttle lever from full forward to full rearward position and read pressure at both gauges.
(5) Line pressure should be 54-60 psi (372-414 kPa) with throttle lever forward and gradually increase to 90-96 psi (620-662 kPa) as lever is moved rearward.

Test Three-Transmission In D Range

This test cheeks pressure regulation and condition of the front and rear clutch circuits. Both test gauges are required for this test.
(1) Connect one test gauge to line pressure port and other gauge to front servo pressure port (Fig. 4). Either gauge can be used at either port.
(2) Start and run engine at 1600 rpm.
(3) Move selector lever two detents rearward from full forward position. This is D range.
(4) Read pressures on both gauges as transmission throttle lever is moved from full forward to full rearward position.
(5) Line pressure should be 54-60 psi (372-414 kPa) with throttle lever forward and gradually in-crease as lever is moved rearward.
(6) Front servo is pressurized only in D range and should be same as line pressure within 3 psi (21 kPa), up to downshift point.

Test Four-Transmission In Reverse

This test checks pump output, pressure regulation and the front clutch and rear servo circuits. Use 300 psi Pressure Test Gauge C-3293 for this test.






(1) Connect pressure test gauge to rear servo port (Fig. 5).
(2) Start and run engine at 1600 rpm for test.
(3) Move valve body selector lever four detents rearward from full forward position. This is Reverse range.
(4) Move throttle lever all way forward then all the way rearward and note gauge readings.
(5) Pressure should be 145 - 175 psi (1000-1207 kPa) with lever forward and increase to 230 - 280 psi (1586-1931 kPa) as lever is moved rearward.

Test Five-Governor Pressure

This test cheeks governor operation by measuring governor pressure response to changes in engine speed. It is usually not necessary to check governor operation unless shift speeds are incorrect or if the transmission will not shift up or down. Use 100 psi Pressure Test Gauge C-3292 for this test.











(1) Connect test gauge to governor pressure port (Figs. 5 and 6).
(2) Move selector lever to D range.
(3) Apply service brakes. Start and run engine a� curb idle speed and note pressure. At idle and with wheels stopped, pressure should be zero to 1-1/2 psi maximum. If pressure exceeds this figure, governor valve or weights are sticking open.
(4) Slowly increase engine speed and observe speedometer and pressure test gauge. Governor pressure should increase in proportion to vehicle speed (approximately 1 psi for every 1 mph shown on speedometer).






(5) Governor pressure rise should be smooth and drop back to 0 to 1-1/2 psi when throttle is closed and wheels are stopped.
(6) Compare results of pressure tests with analysis chart (Fig. 7).