Limited Slip Type
DISASSEMBLY
1. Mark carrier, differential bearing caps and adjusters for reassembly purposes.
2. Remove adjuster lock plates, bearing caps and adjusters, and differential assembly and bearings. Each bearing outer race must remain with its respective bearing.
3. Remove side bearings with puller 49 0839 425C or equivalent and remove ring gear.
4. Alternately loosen case screws to separate case halves.
Fig. 24 Limited slip differential assembly. RX-7:
5. Disassemble differential case assembly in numerical order shown in Fig. 24.
6. Hold pinion flange with holder 49 0259 710A or equivalent and remove drive pinion nut.
7. Remove flange, drive pinion, spacer, rear bearing, and collapsible spacer assembly from carrier.
8. Remove oil seal and front bearing. Remove bearing outer races if necessary by using a drift in the slots provided for this purpose.
DIFFERENTIAL INSPECTION
1. Inspect drive pinion, ring gear, differential gears, and bearings for any damage.
2. Inspect oil seal and pinion flange for wear or damage.
3. Check differential case, pressure rings, and spider for wear or damage.
Fig. 26 Disc, plate & washer thickness chart. RX-7:
4. Inspect friction plates, friction discs, conical springs, and thrust washers for wear or damage. Using micrometer, measure thickness of each part. Refer to Figs. 26 for thickness chart.
DIFFERENTIAL GEARS, ADJUST
1. Measure thickness of the conical springs and record values.
2. On non-turbo models, assemble the following components:
a. Spider and thrust block, if equipped.
b. 2 pressure rings.
c. 4 friction plates.
d. 4 friction discs.
3. On turbo models, assemble the following components:
a. Spider.
b. 2 pressure rings.
c. 2 friction plates.
d. 4 friction discs.
Fig. 28 Checking differential gear clearance (Typical):
4. On all models, using a micrometer, measure dimension L1 excluding the conical spring, Fig. 28.
5. Check clearance No. 1 by subtracting the value and dimension obtained in steps 1 and 4, respectively, from dimension A, Fig. 28. Dimension A is 3.3070 inch (84 mm) for RX-7 non-turbo, 3.5827 inch (91 mm) for RX-7 turbo or 3.5886 inch (91.1 mm) for 1987-88 B2200 and B2600.
6. If clearance is too great, adjust with oversize friction disc. Standard clearance, 0-0.0079 inch (0-0.20 mm) for 1984-85 RX-7, 0-.039 inch (0-.0 mm) for 1986 RX-7, .0020-.0079 inch (.05-.20 mm) for 1987-88 RX-7 non-turbo and 1987-88 B2200 and B2600 or .0039-.0098 inch (.10-.25 mm) for 1987-88 RX-7 turbo. Oversize disc thickness, 0.0827 inch (2.1 mm) for RX-7 or .073 inch (1.85 mm) for 1987-88 B2200 and B2600.
7. Assemble pressure rings, side gears, spider with pinion gears and thrust washers.
8. Using a micrometer, measure dimension L2.
9. Check clearance No. 2 by subtracting L2 dimension obtained in step 8 from dimension B, Fig. 28. Dimension B is 3.4724 inch (88.2 mm) for RX-7 non-turbo, 3.7008 inch (94 mm) for RX-7 turbo or 3.7057 inch (94.1 mm) for 1987-88 B2200 and B2600.
10. If clearance is too great, adjust with oversize thrust washer. Standard clearance, .0063-0.0165 inch (0.16-0.42 mm) for 1984-85 RX-7, .0039-.0094 inch (.08-.24 mm) for 1986 RX-7, .0063-.0189 inch (.16-.48 mm) for 1986 RX-7 non-turbo, .0039-.0157 inch (.10-.40 mm) for 1987-88 RX-7 turbo and 1987-88 B2200 and B2600. Oversize thrust washer, 0.0709 inch (1.8 mm) for RX-7 or .063 inch (1.60 mm) and .067 inch (1.70 mm) for 1987-88 B2200 and B2600.
DRIVE PINION, ADJUST
1. Ensure differential bearing support bores are clean and free of burrs.
2. Install front and rear (center and rear on 1986-888 RX-7) bearing outer races into differential carrier.
Fig. 3 Typical pinion components. Exc. 1986-88 RX-7:
3. On all models except 1986-88 RX-7, proceed as follows:
a. Place a spacer (3), rear bearing (4) and collar B (49 8531 568 for models exc. 1987-88 B2200 and B2600; 49 H027 001 for 1987-88 B2200 and B2600) onto drive pinion model (49 8531 568 for models exc. 1987-88 B2200 and B2600; 49 8531 565 for 1987-88 B2200 and B2600) and secure them with O-ring (6), Fig. 3.
b. Install assembly into carrier, ensuring head of pinion model is secure. Do not install collapsible spacer.
c. Install front bearing (8), collar A (49 8531 567 for models exc. 1987-88 B2200 and B2600; 49 H027 001 for 1987-88 B2200 and B2600) companion flange (9) and washer (10).
d. Install nut and tighten so model turns smoothly.
4. On 1986-88 RX-7 models proceed as follows:
a. Install rear bearing, spacer and drive pinion model (49 F027 001). Install center bearing, long collar, companion flange, washer and nut.
b. Tighten nut so drive pinion model can still be turned by hand.
Fig. 4 Zeroing dial indicator:
5. On all models, install dial indicator to gauge body. Place gauge body on surface plat, Fig. 4, then ``zero'' the dial indicator.
6. Place gauge block (49 0660 555 for RX-7 turbo and B2000, B2200 and B2600 w/P size differential; 49 0305 555 for RX-7 non-turbo and B2200 and B2600 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.
Example:
2 = +0.02 mm (+0.0008 in.)
- 1 = - 0.01 mm ( - 0.0004 in.)
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.
Fig. 5 Pinion spacer chart. One-piece case differential:
10. Select a pinion spacer within a tolerance of + or - 0.0012 in. (0.03 mm) from table, Fig. 5.
PINION BEARING PRELOAD, ADJUST
1. Install the collapsible spacer onto the drive pinion and install them in the carrier.
2. Place the front pinion bearing in position on the pinion. Hold the pinion fully forward and drive the pinion bearing over the pinion until seated.
3. Apply gear lubricant to the lip of the pinion oil seal and install the pinion oil seal into the carrier.
4. Install the companion flange on the pinion by tapping with a plastic hammer.
5. Install the pinion washer and nut. Before tightening the nut (when the pinion preload is zero), determine the oil seal drag by using a torque wrench.
Fig. 6 Measuring pinion bearing preload:
6. Torque pinion nut to 145 ft.lbs. (20 m-kg) for B2000 and B2200 models or 94 ft.lbs. (13 m-kg) for RX-7 models; and check preload, Fig. 6. After preload has been checked, final tightening should be done very cautiously. The pinion nut should be further tightened only a little at a time and preload should be checked after each slight amount of tightening. Exceeding preload specifications will compress the collapsible spacer too far necessitating its replacement. The maximum tightening torque for the nut is 130 ft.lbs. (18 m-kg) for models except B2000 and B2200 models or 253 ft.lbs. (35 m-kg) for B2000 and B2200 models. If the specified preload is not obtained at the maximum torque, replace the collapsible spacer.
7. While observing the preceding step, carefully set the preload drag to 7.8 to 12.2 in. lbs. (9 to 14 cm-kg) for RX-7 models; and 11.3 to 15.6 in. lbs. (13 to 18 cm-kg) for B2000 and B2200 models plus the oil seal drag determined in Step 5. If preload is measured with spring scale at bolt hole of companion flange, the preload drag is 5.5 to 8.8 lbs. (2.5 to 4.0 kg) for RX-7 models; 7.3 to 10.1 lbs. (3.3 to 4.6 kg) for B2000 and B2200 models, Fig. 6.
Fig. 24 Limited slip differential assembly. RX-7:
ASSEMBLY
1. Install parts into differential case as shown in Fig. 24. Center friction discs so splines of side gear can be inserted into friction discs. When assembling differential halves, align identification marks on case edges and tighten attaching screws slightly.
2. Place case assembly in vise and tighten screws securely.
3. Install ring gear and torque to 51-61 ft.lbs. (7.0-8.5 m-kg).
4. Press differential bearings into gear case and install differential bearing outer races to their respective bearings.
5. Install differential gear assembly in carrier.
6. Install adjusters, noting identification marks.
7. Install differential bearing caps according to identification marks and insert attaching bolts.
8. Slightly tighten one bearing cap bolt on each side and adjust backlash.
Fig. 14 Measuring ring & pinion backlash:
BACKLASH, ADJUST
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 0.0075 to 0.0083 inch (0.19 to 0.21 mm) 1984 B2000 and B2200; 0.0035 to 0.0043 inch (0.09 to 0.11 mm) for RX-7, 1986 B2000 and 1987-88 B2200 and B2600.
Fig. 15 Measuring distance between bearing caps:
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 185.5 mm) for RX-7 non-turbo, 1986 B2000 and 1987-88 B2200 and B2600 w/M size differential; 8.0485 to 8.0513 inch (204.428 to 204.5 mm) for 1984 B2000 and B2200, RX-7 turbo and 1987-88 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 to 38 ft.lbs. (3.8 to 5.3 m-kg) for RX-7, 1986 B2000 & 1987-88 B2200 and B2600 w/M size differential; 47 to 56 ft.lbs. (6.5 to 7.7 m-kg) for 1984 B2000 and B2200; 41 to 59 ft.lbs. (5.6 to 8.2 m-kg) for 1987-88 B2200 and B2600 w/P size differential.
4. Install the adjuster lock plates on the bearing caps to prevent the adjusters from loosening.
Fig. 16 Correct pinion to ring gear contact:
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.