Miata 1990-1997

Transmission Removal & Installation

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Fig. Automatic transmission assembly

  1. Shift the selector lever to the N position.
  2.  
  3. Disconnect the negative battery cable. Raise and safely support the vehicle. Drain the transmission fluid.
  4.  
  5. Remove the engine undercover, and disconnect the shift rod.
  6.  
  7. Remove the performance rod.
  8.  
  9. Remove the complete exhaust system from the exhaust manifold.
  10.  
  11. Mark the position of the driveshaft on the rear axle flange, and remove the driveshaft.
  12.  
  13. Disconnect the speedometer cable, and disconnect the vacuum hose from the vacuum diaphragm.
  14.  
  15. Label and disconnect the electrical connectors from the: inhibitor switch, kickdown solenoid, overdrive cancel solenoid, oil pressure switch and lockup solenoid.
  16.  
  17. Remove the dipstick and dipstick tube. Disconnect the oil cooler lines.
  18.  
  19. Support the transmission and differential with jacks. Remove the transmission-to-differential frame as follows:
    1. Disconnect the wiring harness from the frame.
    2.  
    3. Remove the bolts from the underside of the frame at the differential end, noting their location. Pry out the spacer from the frame.
    4.  
    5. Remove the differential mounting spacer from the underside of the differential.
    6.  
    7. Insert a 14 x 1.5mm bolt through the frame hole, and turn it into the sleeve. Twist and pull the bolt downward.
    8.  
    9. Install a 6 x 1mm bolt in the side hole to hold the sleeve, and remove the long bolt. Remove the short bolt.
    10.  
    11. Remove the transmission side bolts, and remove the frame member.
    12.  

  20.  
  21. Remove the torque converter bolts, and the starter.
  22.  
  23. Remove the transmission mounting bolts and remove the transmission, being careful not to drop the torque converter.
  24.  

To install:

  1. Make sure the torque converter is fully installed in the transmission. The distance between 1 of the bolt hole lugs and a straightedge laid across the bellhousing should be 0.89 in. (22.5mm).
  2.  
  3. Raise the transmission into position, and install the mounting bolts. Tighten to 48-66 ft. lbs. (64-89 Nm).
  4.  
  5. Install the starter. Install the torque converter bolts. Align the holes by turning the torque converter. Hold the flexplate with a small prybar, and tighten the bolts to 27-40 ft. lbs. (36-54 Nm).
  6.  
  7. Install the transmission-to-frame member as follows:
    1. Install the differential mounting spacer on the underside of the differential. Tighten the mounting bolts to 38 ft. lbs. (52 Nm).
    2.  
    3. Position the jack under the transmission so the transmission is level.
    4.  
    5. Position the frame and install the transmission side bolts. Snug the bolts.
    6.  
    7. Make sure the sleeve is installed in the block. Install the spacer and bolts with the reamer bolt in the front hole. Snug the bolts.
    8.  
    9. Tighten the transmission side bolts to 77-91 ft. lbs. (104-123 Nm), then tighten the differential bolts to the same specification.
    10.  
    11. Connect the wiring harness to the frame member and remove the jacks.
      NOTE
      After the frame installation, position a straightedge between the body frame members on each side of the vehicle. Measure the distance between the bottom of the frame to the straightedge; it should be 2.023-2.417 in. (51.5-61.5mm). If the distance is not as specified, reposition the frame member at the transmission.



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      Fig. Sleeve and reamer bolt positioning



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      Fig. Measure distance A after installing the transmission-to-differential frame member

    12.  

  8.  
  9. Connect the oil cooler lines, using new gaskets. Install the dipstick tube and dipstick.
  10.  
  11. Connect the electrical connectors and the vacuum hose. Connect the speedometer cable.
  12.  
  13. Install the driveshaft, aligning the marks made during removal. Tighten the bolts to 22 ft. lbs. (30 Nm).
  14.  
  15. Install the exhaust system. Connect the front pipe to the exhaust manifold, using a new gasket, and tighten the nuts to 34 ft. lbs. (46 Nm).
  16.  
  17. Install the performance rod.
  18.  
  19. Install the engine undercover and connect the shift rod.
  20.  
  21. Lower the vehicle and connect the negative battery cable. Fill the transmission with the proper type and quantity of fluid. Start the engine and check for leaks and proper operation.
  22.  

 
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