M/T - Shim Adjustment Procedure
J001/90MANUAL TRANSMISSION SHIM ADJUSTMENTS
APPLICABLE MODELS
1981-90 RX-7 & B-Series
1988-90 929
1989-90 MPV
1990 MX-5 Miata
DESCRIPTION
On vehicles ('81-90 RX-7 and B-Series, '88-90 929, '89-90 MPV, '90 MX-5) with rear-wheel-drive and manual transmissions, the shim adjustments of 5th gear and the mainshaft rear bearing have been changed.
Shown are the new shim adjustment procedures; they will appear in 1991 Workshop Manuals.
There are different shim adjustment procedures for Type-M and Type-R manual transmissions. Use the chart to reference the correct type of transmission.
M-TYPE
5th Gear
1. Install the synchronizer ring and 5th gear.
2. Insert the steel ball and thrust washer.
3. Install only the two 3.0 mm (0.118 in) thick "C" washers in the front mainshaft groove and hold them with the retaining ring.
NOTE:
If the "C" washers are not pushed fully forward in the mainshaft groove the measurement will be incorrect.
4. While pushing the "C" washers forward, measure the clearance between the thrust washer and "C" washers.
If the clearance is not as specified select the proper thrust washer.
Standard clearance:
Refer to the workshop manual for the vehicle being repaired.
Mainshaft Rear Bearing
1. Drive on the mainshaft rear bearing using the SST, fully seating it against the front "C" washers.
2. Install the original "C" washers and hold them with the retaining ring.
NOTE:
If the "C" washers will not fit into the rear mainshaft groove, select the proper thickness "C" washers.
Ensure both "C" washers at this position are the same thickness.
3. Measure the clearance between the "C" washers and mainshaft rear bearing.
If the clearance is not as specified, select the proper "C" washers.
Standard clearance:
Refer to the workshop manual for the vehicle being repaired.
R-TYPE
5th Gear
1. Install the synchronizer ring and 5th gear.
2. Install the steel ball and thrust washer.
3. Install only the two 3.0 mm (0.118 in) thick "C" washers in the front mainshaft groove and hold them with the retaining ring.
NOTE:
If the "C" washers are not pushed fully forward in the mainshaft groove the measurement will be incorrect.
4. While pushing the "C" washers forward, measure the clearance between the "C" washers and thrust washer.
If the clearance is not as specified, select the proper thrust washer.
Standard clearance:
Refer to the workshop manual for the vehicle being repaired.
Mainshaft Rear Bearing
1. Drive on the mainshaft rear bearing using a suitable pipe, fully seating it against the front "C" washers.
2. Install the original "C" washers and hold them with the retaining ring.
NOTE:
If the "C" washers will not fit into the rear mainshaft groove, select the proper thickness "C" washers.
Ensure both "C" washers at this position are the same thickness.
3. Measure the clearance between the "C" washers and mainshaft rear bearing. If the clearance is not as specified, select the proper "C" washers.
Standard clearance:
Refer to the workshop manual for the vehicle being repaired.
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