Backlash

Fig. 14 Measuring Ring & Pinion Backlash:

Fig. 15 Measuring Distance Between Bearing Caps:

Fig. 16 Correct Pinion To Ring Gear Contact:

1. Check the backlash between ring gear and drive pinion. With wrench (490259 720), Fig. 14, turn both bearing adjusters equally until the backlash becomes; 0.0035 to 0.0043 inch (0.09 to 0.11mm) for RX-7, B2200 and B2600.
2. Preload on the differential bearings is obtained by tightening the adjusters. Tighten the adjusters until the distance between both pilot sections on bearing caps is 7.3004 to 7.3033 inch (185.428 to 185.5mm) for RX-7 non-turbo, B2200 and B2600 w/M size differential; RX-7 turbo, B2200 and B2600 w/P size differential, Fig. 15. When adjusting preload, care must be taken not to disturb backlash of drive pinion and ring gear.
3. Torque bearing cap bolts to 27-38 ft. lbs. for RX-7, B2200 and B2600 w/M size differential; 47-56 ft. lbs. for B2200 and B2600 w/P size differential.
4. Install the adjuster lock plates on the bearing caps to prevent the adjusters from loosening.
5. Check the tooth contact of the ring gear pinion by applying a thin coat of red lead on both sides of about six to eight ring gear teeth and rotating the ring gear a few times in both directions. Pinion position and backlash contact pattern should be as shown in Fig. 16.