Service Manual 5008734_40-90 HP Gearcase [Gearcase Assembly]

between the gauge bar and the bearing housing between each pair of screw holes. Replace the bearing housing and repeat check if variance is greater than 0.004 in. (0.101 mm).

Check squareness of the pinion to the driveshaft. Hold the shim gauge bar against the bearing housing (between the screw holes) while rotating just the driveshaft and pinion assembly. Measure clearance between the gauge bar and the pinion at several locations. If variance is greater than 0.002 in . (0.050 mm) replace the pinion or driveshaft, as necessary, and repeat check.

Subtract the average clearance measurement from 0.020 in. (0.508 mm) to determine the correct shim thickness required. Select the fewest number of shims to achieve the correct thickness.

Remove the driveshaft from the tool and add the required shims between the bearing housing and the thrust washer.

IMPORTANT: Use extreme care when removing bearing housing to avoid damaging the seals. Use Driveshaft Seal Protector, P/N 312403.

Check clearance again. The measurement between the gauge bar and pinion should be 0.020 in. (0.508 mm).

Remove the nut and pinion from the driveshaft. Discard the nut.

Shift Housing, Gear, and Propeller Shaft Installation

Push shifter detent into farthest downward position. Tip the rear of the gearcase slightly downward to assist in the installation of the shaft assembly.

Be sure the thrust bearing and the thrust washer are in the proper position. Insert the shaft assembly fully in to the gearcase while aligning shift housing pin with hole in forward end of gearcase housing.

1.Pin

Shift Rod Housing Installation
Lubricate a new shift rod cover O-ring with Triple-Guard grease. Install the O-ring into the shift rod cover.

IMPORTANT: Make sure O-ring is fully seated in groove.

1. O-ring
2. Groove

Apply Triple-Guard grease to the threaded end of the shift rod and insert it through the cover. Turn the shift rod while pushing it through the cover to avoid damaging the O-ring.

Apply Gasket Sealing Compound to both sides of a new shift rod cover gasket. Place the gasket on the gearcase. Thread the shift rod in to the shifter detent about four turns.

1. Cover gasket

Move shift rod from side to side while pushing on the propeller shaft to ensure proper alignment of the bearing housing locator pin into the pin hole in the gearcase.

Apply Gasket Sealing Compound to the threads of the shift rod cover screws. Tighten the screws to a torque of 60 to 84 in. lbs. (7 to 9.5 N·m).

Place the cover seal on the shift rod cover.

1. Cover seal

Pinion Gear and Driveshaft Installation

Refer to DRIVESHAFT SHIMMING on p. 312 before proceeding.

Install new seals in driveshaft bearing housing. Refer to Driveshaft Bearing Housing Service on p. 309.

Place the driveshaft thrust bearing, thrust washer, and correct shim(s) on the driveshaft as shown.

1. Thrust bearing
2. Thrust washer
3. Shim(s)

Lightly apply Gasket Sealing Compound to the gearcase are a that contacts mounting flange of the driveshaft bearing housing. Do not coat inside bearing housing bore surface of the gearcase.

Adjust shift rod to move clutch dog as far forward as possible. Be sure excess grease is removed from the pinion bearing.

IMPORTANT: The inside taper of the pinion gear and the driveshaft taper MUST be completely free of grease. Clean the tapers with Cleaning Solvent. Use a shop towel free of grease and lint.

Place the pinion gear into the gearcase. Insert the driveshaft into the gearcase and through the pinion gear.

Using Driveshaft Seal Protector , P/N 312403, slide the driveshaft bearing housing onto the driveshaft and into position in the gearcase. Align the embossed word “FRONT” toward the shift rod. Do not install screws at this time.

1. Seal protector

Lightly coat the threads of a new pinion nut with outboard lubricant. Use Pinion Nut Starting Tool, P/N 320675, to install nut on the driveshaft. Turn the driveshaft by hand to thread the nut on to shaft.

Apply Gasket Sealing Compound to the threads of the driveshaft bearing housing screws. Tighten screws in stages to a torque of 96 to 120 in. lbs. (11 to 14 N·m).

1. Driveshaft bearing housing screws

Use Driveshaft Holding Socket, P/N 334995, and an 11/16 in. open-end wrench, to tighten the pinion nut to a torque of 40 to 45 ft. lbs. (54 to 60s N·m). Pad handle of the wrench to prevent damage to gearcase.

1. Holding socket
2. 11/16 Wrench

Propeller Shaft Bearing Housing and Gear Installation
Place the small thrust washer in recess of the reverse gear.

1. Small thrust washer

Oil and install thrust bearing and larger thrust washer on hub of reverse gear. Slide the gear assembly onto the propeller shaft until it engages the pinion gear.

1. Thrust bearing
2. Thrust washer

Slide the bearing housing retainer plate into position over the propeller shaft.

1. Retaining ring

Using Retaining Ring Pliers, P/N 331045, install the two retaining rings.

Retaining rings are under extreme pressure during installation. Wear safety glasses and proceed with care to avoid unsnapping the ring from the pliers.

Make sure the retaining rings are seated in the grooves in the gearcase.

1. Retaining ring

Thread two Guide Pins, P/N 383175, into the retainer plate to align holes in the plate with holes in the propeller shaft bearing housing. Do not thread guide pins more than two turns into the retainer plate.

1. Guide pin

Install O-ring in groove in the bearing housing. Lightly apply Gasket Sealing Compound to the O-ring flange and aft support flange of the bearing housing. Do not allow sealer to contact either forward thrust surface or bearings in the housing.

Align the bearing housing on the guide pins with the word “UP” toward the top. Place the housing into gearcase and tap the housing with a soft face mallet to seat the O-ring.

Apply Gasket Sealing Compound to the threads and seals of the four propeller housing retaining screws. Install two of the screws into the bearing housing finger tight. Remove the guide pins and install the remaining two screws. Tighten all four screws to a torque of 120 to 140 in. lbs. (14 to 16 N·m).

Final Assembly and Adjustment
To complete gearcase assembly, refer to:
• GEARCASE LEAK TEST on p. 295
• WATER PUMP SERVICE on p. 298
• SHIFT ROD ADJUSTMENT on p. 300
• GEARCASE REMOVAL AND INSTALLATION on p. 296
• Gearcase Lubricant on p. 39
• Propeller Hardware Installation on p. 294
• Trim Tab Adjustment on p. 31.

During break-in period of a reassembled gearcase, change the gearcase lubricant between 10 to 20 hours of operation.