Mazda Trucks 1994-1998 Repair Guide

Vacuum Diaphragm

Print

Only Navajo, 1994 B Series Pick-up and 1994-95 MPV models (with the hydraulically controlled automatic transmission) use a vacuum diaphragm (or modulator). All other automatic transmissions are PCM controlled and do not require vacuum supply from the engine.

REMOVAL & INSTALLATION



Navajo and 1994 B Series Pick-up Models

See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Remove the vacuum diaphragm retaining clamp and bolt, then pull the diaphragm out of the transmission

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the vehicle safely.
  4.  
  5. Disconnect the hose from the vacuum diaphragm.
  6.  
  7. Remove the vacuum diaphragm retaining clamp bolt and clamp. Do not pry on the clamp.
  8.  
  9. Pull the vacuum diaphragm from the transmission case and remove the vacuum diaphragm control rod from the transmission case.
  10.  

To install:
  1. Install the vacuum diaphragm control rod from the transmission case.
  2.  
  3. Push the vacuum diaphragm into the case and secure it with the clamp and bolt. Tighten to 80-106 inch lbs. (9-12Nm).
  4.  
  5. Fit the vacuum hose to the diaphragm.
  6.  
  7. Lower the vehicle.
  8.  
  9. Reconnect the negative battery cable.
  10.  

MPV Models Equipped with the Hydraulically Controlled Transmission

See Figures 2 and 3

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the vehicle safely. Place a fluid drain pan under the transmission oil pan.
  4.  
  5. Loosen the transmission oil pan mounting bolts and drain approximately 1 quart of transmission oil. After draining the oil, tighten the oil pan bolts back up again.
  6.  
  7. Disconnect the hose from the vacuum diaphragm.
  8.  
  9. Remove the vacuum diaphragm, O-ring seal and vacuum diaphragm rod.
  10.  



Click image to see an enlarged view

Fig. Fig. 2: Pull the vacuum diaphragm straight out of the transmission



Click image to see an enlarged view

Fig. Fig. 3: Replace the vacuum diaphragm O-ring seal

To install:
  1. Apply ATF to a new O-ring seal and install it onto the vacuum diaphragm.
  2.  
  3. Apply ATF to the vacuum diaphragm and rod, then install them into the transmission.
  4.  
  5. Fit the vacuum hose to the diaphragm.
  6.  
  7. Lower the vehicle.
  8.  
  9. Add approximately 1 quart of ATF to the transmission, then check the level.
  10.  
  11. Reconnect the negative battery cable.
  12.  
  13. Warm up the engine to normal operating temperature and check the system for fluid and vacuum leakage.
  14.  

 
label.common.footer.alt.autozoneLogo