Drive Pinion

1. Ensure differential bearing support bores are clean and free of burrs.
2. On RX-7 models, install center and rear bearing outer races into differential carrier.
3. On all models except RX-7, proceed as follows:
a. Install front and rear bearing outer races into differential carrier.
b. Place a spacer (3), rear bearing (4) and collar B (tool No. 49 8531 568, or equivalent, for models except 1993 Pickups; tool No. 49 H027 001, or equivalent, for 1993 Pickup models) onto drive pinion model (tool No. 49 8531 568, or equivalent, for models except 1993 Pickups; tool No. 49 8531 565, or equivalent, for 1993 Pickup models) and secure them with O-ring (6), Fig.8 .

Fig. 8 Pinion Components:

c. Install assembly into carrier, ensuring head of pinion model is secure. Do not install collapsible spacer.
d. Install front bearing (8), collar A (tool No. 49 8531 567, or equivalent, for all models except 1993 Pickups; tool No. 49 H027 001, or equivalent, for 1993 Pickup models), companion flange (9) and washer (10).
e. Install nut and tighten so model turns smoothly.

4. On RX-7 models, proceed as follows:
a. Install rear bearing, spacer and drive pinion model (tool No. 49 F027 001, or equivalent). Install center bearing, long collar, companion flange, washer and nut.
b. Tighten nut so drive pinion model can still be turned by hand.

5. Install dial indicator to gauge body. Place gauge body on surface plate, Fig. 9, then zero the dial indicator.

Fig. 9 Dial Indicator Reset:

6. Place gauge block (tool No. 49 0660 555, or equivalent, for RX-7 turbo and 1993 Pickups w/P size differential; tool No. 49 0305 555, or equivalent, for RX-7 non-turbo and 1993 Pickups w/M size differential) on drive pinion model and carefully place the gauge body adjusted in step 5 on gauge block so feeler of indicator comes in contact with lowest portion of differential bearing support bore.
7. Measurement should be taken on each bearing support bore. Record an average of reading:
a. If average is on plus side, use a spacer which is thicker by the plus value than the spacer used in step 3 or 4.
b. If average is on minus side, use a spacer which is thinner by the minus value than the spacer used in step 3 or 4.

8. Remove the gauge body and dial indicator, and check zero setting on the surface plate to make sure setting was not disturbed by handling.
9. To compensate for machining variables, the pinion has a number recorded in hundredth millimeters on the pinion face of the tapered end.
a. If the pinion is marked with a plus number, subtract the specified amount on the pinion face of the tapered end from the amount determined in step 7.
b. If the pinion is marked with a minus number, add the specified amount on the pinion face of tapered end to the amount determined in step 7.

10. Select a pinion spacer within a tolerance of ±0.0012 inch 0.03 mm) from table, Fig. 10.

Fig. 10 Pinion Spacer Chart: