1991 MAZDA MIATA differential

Fig. 6: View of Power Plant Frame Components (Miata)
Courtesy of MAZDA MOTORS CORP.

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
Microsoft
Sunday, July 05, 2009 2:17:01 PMPage 11 © 2005 Mitchell Repair Information Company, LLC.

Fig. 7: Removing Reamer Bolt Sleeve (Miata)
Courtesy of MAZDA MOTORS CORP.
OVERHAUL
DIFFERENTIAL HOUSING & DRIVE PINION
Disassembly
1. Mount carrier in repair stand. Mark side bearing caps for reassembly purposes. Remove adjuster lock
plates. See Fig. 8
.
2. Loosen side bearing and slightly back off adjusters. Remove bearing caps and adjusters. Withdraw
differential assembly from carrier. Ensure side bearing races remain with their respective bearings.
3. Remove drive pinion lock nut. Remove companion flange using a gear puller. Remove drive pinion,
spacer, rear bearing and collapsible spacer assembly from carrier. Remove oil seal and front bearing.
NOTE: Mark position of all components before disassembly.

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
Microsoft
Sunday, July 05, 2009 2:17:01 PMPage 12 © 2005 Mitchell Repair Information Company, LLC.

Remove bearing outer races, using a drift and hammer in slots provided on inner lip (if necessary).
Fig. 8: Exploded View of Typical Differential & Carrier Assembly

Courtesy of MAZDA MOTORS CORP.
DIFFERENTIAL ASSEMBLY & RING GEAR
Disassembly
1. Using Puller (49 0839 425C ), remove side bearings from gear case. Ensure side bearings are marked for

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
Microsoft
Sunday, July 05, 2009 2:17:01 PMPage 13 © 2005 Mitchell Repair Information Company, LLC.

reassembly purposes. Separate ring gear from gear case. On standard differentials, remove knock pin.
Remove pinion shaft, pinion gears, thrust washers and side gears. See Fig. 8
.
2. On Limited Slip Differentials (LSD) models, gradually loosen attaching screws until distance between
left and right half of differential case is about 0.12" (3 mm). On all models, mark differential halves for
reassembly reference.
3. Carefully separate differential halves. On LSD models, remove thrust washer, conical springs, friction
plates, friction discs, pressure ring, side gears, carrier pinion (spider) gears and spider. See Fig. 9
. Keep
parts in order for reassembly.
Fig. 9: View of Limited Slip Differential (LSD) Assembly (RX7)

Courtesy of MAZDA MOTORS CORP.
STANDARD DIFFERENTIAL
Reassembly & Adjustment
1. Install side gears, thrust washers, thrust block, pinion gears, pinion shaft and knock pin. Stake knock pin.
Press side bearings onto differential assembly. Position a dial indicator against pinion gear. Secure one
side gear. See Fig. 10
.
2. Check side gear and pinion gear backlash. If backlash exceeds .004" (.10 mm), replace thrust washers.
Apply locking compound to rear face of ring gear. Install ring gear and tighten ring gear retaining bolts to
51-61 ft. lbs. (69-83 N.m). See CARRIER PINION THRUST WASHER SPECIFICATIONS
.

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
Microsoft
Sunday, July 05, 2009 2:17:01 PMPage 14 © 2005 Mitchell Repair Information Company, LLC.

CARRIER PINION THRUST WASHER SPECIFICATIONS
Fig. 10: Measuring Carrier Gear Backlash

Courtesy of MAZDA MOTORS CORP.
LIMITED SLIP DIFFERENTIAL (RX7)
1. Check friction plate, disc and thrust washer thicknesses. See RX7 DIFFERENTIAL
SPECIFICATIONS . Measure and record thickness of 6 plate springs.
2. Measure thickness of complete clutch pack excluding conical springs. See Fig. 9
. Subtract conical spring
thickness and complete clutch pack thickness from 3.583" (91.00 mm). Difference should be .004-
010" (.10-.25 mm).
3. If clearance is excessive, use oversize friction discs. Oversize friction disc thickness is .0827" (2.10 mm).
Measure thickness of side gears, pressure rings, spider, pinion gears and thrust washers in place. See Fig.
9 .
Identifying MarkThickness In. (mm)
0.0787 (2.00)
05.0807 (2.05)
1.0827 (2.10)
15.0846 (2.15)
2.0866 (2.20)

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
Microsoft
Sunday, July 05, 2009 2:17:01 PMPage 15 © 2005 Mitchell Repair Information Company, LLC.

4. Subtract thickness from 3.701" (94.00 mm). Difference should be .004-.016" (.10-.40 mm). If clearance is
not as specified, install oversize thrust washers. See RX7 DIFFERENTIAL SPECIFICATIONS
.
5. Install parts in proper order. See Fig. 8
. Before installing thrust washers, coat with grease. When
installing conical springs, ensure concave side faces side gears. Align differential case and cover
alignment marks. Apply locking compound to rear face of ring gear. Install ring gear and tighten ring gear
retaining bolts to 51-61 ft. lbs. (69-83 N.m).
RX7 DIFFERENTIAL SPECIFICATIONS (LIMITED SLIP)
Pinion Assembly (B2200, B2600i, Miata, Protege 4WD & 929)
1. Using a press, install pinion bearing races in differential housing. Place original spacer, rear bearing and
Bearing Collar (49 H027 001 ) onto Drive Pinion (49 8531 565 ). Secure collar with "O" ring. Install
assembly into differential housing.
2. Install front bearing, Collar (49 8531 567 on 929 or 49 U027 001 on B2200 and B2600i), companion
flange, washer and original drive pinion nut. See Fig. 11
. Tighten flange nut so assembly can be turned
by hand.
3. Place a dial indicator on Pinion Height Gauge (49 0727 570 ). Place pinion height gauge on a flat surface
and zero dial indicator. Position Gauge Block on top of Drive Pinion (49 F027 001 ). See GAUGE
BLOCK SELECTION .
GAUGE BLOCK SELECTION
ApplicationIn. (mm)
Friction Disc Thickness
Standard.079 (2.0)
Limit.075 (1.9)
Friction Plate
Standard.079 (2.0)
Limit.075 (1.9)
Oversize.083 (2.1)
Thrust Washer
Standard.063 (1.6)
Limit.055 (1.4)
Oversize.071 (1.8)
ApplicationUse Gauge Block No.
Front Differential
B2600i
& MPV
4WD49 0305 555
Rear Differential
B220049 0305 555
B2600i,
Protege 49 0660 555

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
Microsoft
Sunday, July 05, 2009 2:17:01 PMPage 16 © 2005 Mitchell Repair Information Company, LLC.

4. Set pinion height gauge on top of gauge block. Set dial indicator to measure distance to a point where
side bearing sits. Measure lowest point. See Fig. 11
. Measure both sides. Add both measurements
together and divide sum by 2.
5. If measurement is not zero, replace pinion spacer. Spacers are available in a range of .1213-
.1366" (3.081-3.470 mm), in .001" (.03 mm) increments. Remove dummy pinion shaft. Press rear pinion
bearing on pinion shaft.
6. Install pinion shaft, spacer, front bearing, collapsible spacer and companion flange in differential housing.
DO NOT install pinion seal at this time. DO NOT exceed one ton force or collapsible spacer will be
damaged.
7. Temporarily tighten drive pinion nut. Turn companion flange by hand to seat bearing. Tighten drive
pinion nut to 94-130 ft. lbs. (128-177 N.m). Check pinion bearing preload, at drive pinion nut. See
PINION PRELOAD SPECIFICATIONS
. If pinion bearing preload is not as specified, replace
collapsible spacer and recheck preload.
8. Remove drive pinion nut and companion flange. Install pinion seal. Apply oil to seal lip. Install
companion flange. Using a new drive pinion nut, tighten nut to 94-130 ft. lbs. (128-177 N.m). Recheck
pinion bearing preload.
PINION PRELOAD SPECIFICATIONS
4WD &
929
Miata49 N027 001
ApplicationINCH lbs. (N.m)
B2200 & 92911.3-15.6 (1.3-1.8)
B2600i 4WD
Front11.3-15.6 (1.3-1.8)
Rear7.8-12.2 (0.9-1.4)
Miata & Protege 4WD (Rear)2.6-6.1 (0.3-0.7)
MPV 4WD
Front7.8-12.2 (0.9-1.4)
Rear11.3-15.6 (1.3-1.8)
RX7
Non-Turbo7.8-12.1 (0.9-1.4)
Turbo11.3-15.6 (1.3-1.8)

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
Microsoft
Sunday, July 05, 2009 2:17:01 PMPage 17 © 2005 Mitchell Repair Information Company, LLC.

1991 Mazda MX-5 Miata
1990-91 DRIVE AXLES Differentials & Drive Axles - 929, B2200, B2600i, MX-5 Miata, MPV, Protege & RX-7
Microsoft
Sunday, July 05, 2009 2:17:01 PMPage 18 © 2005 Mitchell Repair Information Company, LLC.