In-Shop Test

The shift speed test can be performed in-shop to check shift valve operation, governor circuits, shift delay pressures, throttle boost and downshift valve action.

1. Raise and support vehicle so that rear wheels are clear of floor. Disconnect and plug line to vacuum diaphragm. Connect an adjustable vacuum source to vacuum diaphragm unit.
2. Start vehicle. Apply 18 in. Hg vacuum to vacuum diaphragm unit. Shift transmission into Overdrive position. At minimum throttle position, allow transmission to shift through gears and into converter lock-up.
3. Note shift speeds and compare against appropriate SHIFT SPEEDS table. If shift speeds are not within specifications, proceed to GOVERNOR PRESSURE TEST  to isolate problem.
4. If shift speeds are within specifications, the 1-2, 2-3, 3-4 and converter clutch shift valves and governor are okay. Shift to Neutral position. Run engine at 1000 RPM for 15 seconds to cool transmission. Proceed to next step.
5. Apply 1-2 in. Hg vacuum to vacuum diaphragm unit. Shift transmission into Overdrive position. Allow transmission to shift from 1-2.
6. If shift speed is within specification, throttle boost and shift delay systems are functioning properly. Shift to Neutral position. Run engine at 1000 RPM for 15 seconds to cool transmission. Proceed to next step.
7. Apply 1-2 in. Hg vacuum to vacuum diaphragm unit. Shift transmission into Overdrive position. Move the kickdown linkage through detent into wide open throttle position. Allow transmission to shift from 1-2. Shift speed should be higher than normal specification.