FIRST CLUTCH MAINTENANCE (Contd)
CLEANING AND INSPECTION
The first clutch backplate is a selective part marked by
number 4, 5, or 6. Identify and record backplate number if
inspection indicates need for replacement.
Volatile mineral spirits burn easily and fumes can explode. Do not
smoke or allow flames nearby when using volatile mineral spirits.
Failure to do so may cause serious injury or death to personnel.
1. All metallic parts should be cleaned thoroughly with mineral spirits and dried with a lint-free rag.
2. Inspect backplate (4) for scratches, scores, burrs, and wear. Remove minor scratches and burrs with
crocus cloth. Measure thickness of backplate (4) (refer to table 1, First Clutch Backplate Thickness,
for proper measurement). Replace backplate (4) if damaged or worn less than minimum thickness.
Table 1. First Clutch Backplate Thickness.
0.683 - 0.693
17.35 - 17.60
0.647 - 0.657
16.43 - 16.69
0.611 - 0.621
15.52 - 15.77
3. Measure thickness of internal-splined clutch plates (2) and (5). Replace-internal splined clutch
plate(s) (2) and (5) if thickness is less than 0.090 in. (2.29 mm).
4. Place external-tanged clutch plates (1) on clean, level surface. Measure distance from inside
diameter to level surface. Replace external-tanged clutch plate(s) (1) if distance is more than
0.010 in. (0.25 mm).
5. Inspect springs (8) for broken coils, wear, and discoloration due to overheating. Replace
spring(s) (8) if broken, worn, or discolored. Springs (8) should be solid yellow or solid orange with
yellow stripe. Using spring tester, check spring load (refer to table 2, First Clutch Spring Wear
Limits, for proper measurement). Replace spring(s) (8) if not within limits.
6. Inspect snapring (3), snapring retainer (7), and piston (9) for scratches, scores, burrs, and wear.
Remove minor scratches and burrs on travel and seal surfaces with crocus cloth. Replace if
7. Inspect ring gear (6) teeth for burrs. Remove burrs with crocus cloth. Replace ring gear (6) if damaged.
Table 2. First Clutch Spring Wear Limits.
1.53 in. (38.9 mm)
1.01 in. (25.7 mm)
1.28 in. (32.5 mm)
0.95 in. (24.1 mm)