UPPER GEAR CASE-ASSEMBLY
NOTE; Optimum performance of the upper gear case requires “setting up” the pinion &
clutch gears with IMCO procedure as follows.
1.
Take all measurements using the “SCX4 Setup Diagrams” (Fig 3) and the “SCX
Work Sheet” (Fig 4).
2.
After all measurements are taken and proper race thickness has been
determined, place lower race [2-6] and thrust bearing [2-7] in case.
3.
Place lower clutch gear [2-13] with attached tool (backlash tower 01-5579) into
case.
4.
Adjust rolling preload (8-10 in/lbs) on pinion gear by changing Yoke Gear End
Shims [2-42]. Tighten nut [2-36] to 75 ft/lbs.
5.
After proper rolling preload is determined, assemble pinion pack with pinion
retainer nut “O” ring [1-20] between pinion seal carrier [2-45] and retainer nut
[2-31].
6.
Torque retainer nut to 200 ft/lbs. ((Tool: Pinion Retainer Nut Driver 01-5590)
(torque wrench centered on retainer nut or if using longer tool be sure to
compensate on torque value). Use new lock nut [2-36] and torque to 75 ft/lbs.
7.
Install pinion pack using 4 screws [1-23] for testing.
8.
Install dial indicator (indicator bracket 01-5588) and pinion gear locking tool
(pinion gear lock 01-5587) Fig-5.
9.
Check backlash, adjust backlash with pinion hub shims [2-18] (average backlash
should be .006-.008.
10.
Once backlash is determined check upper clutch gear by placing gear in lower
position with lower thrust race and backlash tower. This will insure backlash is
.006 -.008 is correct on upper gear.
11.
Assemble drive shaft gear assembly [2-(8-17)].
12.
Place the lower clutch gear [2-13] onto the clutch shaft [2-17], allowing it to rest
on the thrust collar.
13.
Place the lower clutch spring thrust bearing [2-14] (silver side “up), lower clutch
spring [2-15], clutch cone [2-16], upper clutch spring [2-15], upper clutch spring
thrust bearing [2-14], (Note; use a thin layer of grease between the bearing and
the gear to keep bearing in place during assembly), (silver side “down”), upper
clutch gear [2-13], clutch shaft retainer [2-9] onto the upper clutch shaft [2-17].
14.
Compress the upper clutch gear and install the upper drive shaft retainer
keepers [2-8].
15.
Install complete clutch shaft assembly into gear case.
16.
Align the clutch gear timing marks (“+” over “-“, or “-“ over “+”) with the center of
the rear face of the gear case.
17.
Install pinion pack with “O” ring [1-19] and shims [2-18] (shims must be properly
aligned).
18.
Torque pinion pack screws [1-(22-23)] (important: make sure copper sealing
washers [1-21] are in place, short screws in 2 top holes & 2 bottom holes [1-22]
longer screws in 3 port & 3 starboard holes [1-23] to 20 ft/lbs. Use “Loctite 242”
on all screws. Note: make sure that the clutch gear timing marks align to case
timing marks, roll pinion to check.
Page 6
