Transmission Disassembly
- Remove transmission and place on work stand. Remove torque converter and drain ATF fluid out extension housing. Remove governor tube, downshift solenoid, vacuum diaphragm (with rod), oil pressure switch, OD solenoid and lock-up control solenoid. Match mark converter housing-to-OD case and OD case-to-main case.
- Remove converter housing bolts and remove housing. Remove OD case as an assembly. Remove oil pan and discard gasket. Valve body uses different size bolts. Note location of each during removal and remove bolts and- valve body assembly. DO NOT drop manual valve.NOTE: Mazda RX7 2nd band servo assembly uses a spacer and snap ring on piston stem. Use care during disassembly as band cannot be applied.
- Remove OD band servo cover. Loosen piston stem lock nut and tighten piston stem to apply band. Repeat procedure for 2nd band servo (except Mazda RX7). Remove OD case assembly from main case. Mark direction of input shaft and remove from OD case. N4A-EL input shaft cannot be removed at this time. Mark direction of intermediate shaft and remove.
- Screw in 2 slide hammer type pullers into oil pump, across from each other. Remove oil pump. Loosen OD band servo piston stem. Remove OD Planetary gear and direct clutch as an assembly. Remove bearing, race, trust washer, brake band and strut. Clip brake band to retain. See Fig 1 .
- Lightly tap servo retainer and remove OD servo assembly. Remove accumulator snap ring. Apply compressed air to oil passage and remove accumulator plug, piston and spring. See Fig 2 . On Mazda vehicles only, measure accumulator and cancel spring free length. Accumulator spring free length should be approximately 1.560" (39.70 mm). Cancel spring free length for 1990 only should be approximately .906" (23.00 mm). On all models, match mark OD case to drum support. Remove bolts retaining drum support to OD case. Remove gaskets. Remove speedometer pinion from extension housing.
- On Mazda RX7 models, remove 2nd brake band servo clip, retaining piston stem. Remove 2nd band servo assembly, brake band and strut. Retain brake band with clip. See Fig 1 . Insert clip back on piston stem. Remove front clutch, rear clutch, rear clutch hub, front planetary pinion carrier, connecting shell and sun gear as an assembly.
- On all models (except Mazda RX7), loosen 2nd brake band servo piston stem and remove strut. Remove brake band, front clutch, rear clutch, rear clutch hub, front planetary pinion carrier, connecting shell and sun gear as an assembly. Remove bolts retaining 2nd brake band servo. Apply air to remove servo assembly. See Fig 3 .
- On all models, check one-way clutch for proper operation. See Fig 4 . Remove rear planetary carrier snap ring. Remove rear planetary carrier. Remove output shaft snap ring. Remove connecting drum with internal gear.
- Pry out one end of low and reverse brake snap ring. Using pliers, remove snap ring by rotating end of snap ring counterclockwise. Remove low and reverse clutch pack. Remove extension housing using care not to lose parking pawl components.
- On Nissan models, remove output shaft and governor as an assembly. On Mazda models, remove output shaft and then remove governor assembly from main case. Mazda N4A-EL does not have governor attached to oil distributor on output shaft.
- On all models, remove thrust washer and bearing from rear of transmission. Remove one-way clutch bolts. Remove one-way clutch inner race, thrust washer, return spring and thrust ring. Apply air to oil passage to remove low and reverse brake piston. See Fig 5 .