Modulating Pressure
NOTE:
Modulating pressure port is next to vacuum control unit at 4 o'clock position. Disconnect vacuum line, and measure while driving at approximately 30 MPH.
- Disconnect vacuum hose and remove rubber cap from vacuum control unit. Connect pressure gauge to modulating pressure port. Drive vehicle approximately 32 MPH or more. Measure and record modulating pressure. See the MODULATING PRESSURE SPECIFICATIONS table. If pressure is within specification, adjustment of modulating pressure is not necessary. If pressure is not within specification, go to next step.
- Put transmission in park. Apply parking brake. Pull locking plate out of locking slots to permit rotation. See Fig 1 . Turning adjustment screw in vacuum control results in pressure change of about 6 psi (.4 bar). Adjust to correct value. Refer to the MODULATING PRESSURE SPECIFICATIONS table.
- After turning the adjustment screw, push the locking plate back into the locking slots. Drive the vehicle approximately 32 MPH or more. Measure and record modulating pressure. Refer to specifications in the MODULATING PRESSURE SPECIFICATIONS table.
- If pressure is within specification, go to next step. If adjustment will not bring vehicle within specification, replace centrifugal governor.
- Put rubber cap back on vacuum control unit. Connect vacuum hose. Install screw on vacuum line holder (if equipped).
MODULATING PRESSURE SPECIFICATIONS
| Model | psi (bar) |
|---|---|
| Vehicle Speed Greater Than 32 MPH | 7.3 (.5) Or More |