847823A 1 Mercruiser GEAR SET (Pinion and Drive)

The gearbox has three output gears driven by a single input gear or pinion, all of which are straddle mounted on ball bearings. Power is transmitted from the engine to the pinion by a splined input shaft that mates with the pinion on one end and with the hub of the drive plate on the other end. The drive plate bolts to the engine flywheel. The engine adapter bolts to the engine flywheel housing and supports the rest of the gearbox.Lubrication
The oil level in the gearbox should be kept at check plug level to ensure proper lubrication of internal components.Under normal operating conditions the SAE 90 gear lubricant (GL) specified in General 2.0-1 should be used; however the lubricant should be changed if the operating temperatures are higher or lower than normal:1. If the gearbox case temperature is consistently above 220 degrees Fahrenheit (104 degrees Celsius), use an oil with a viscosity of SAE 140.2. If the atmospheric temperature is 30 degrees Fahrenheit (-1.1 degrees Celsius) and above, use an oil with a viscosity of SAE 90.3. If the atmospheric temperature is 50 degrees Fahrenheit (9.9 degrees Celsius) and below, use an oil with a viscosity of SAE 30.Internal and external splines should be liberally greased whenever the gearbox drive shaft or a hydraulic pump is replaced.Removing The Pump Drive Gearbox
INADVERTENT ENGAGEMENT OF THE GROUND DRIVE SYSTEM COULD CAUSE PERSONAL INJURY. STOP THE ENGINE AND REMOVE THE KEY FROM THE IGNITION SWITCH.
1. Set the battery disconnect switch at "Off". 2. Remove the engine air cleaner hood and air inlet ducting, then raise the plate from over the pumps. 3. Drain the lubricant from the gearbox. 4. Thoroughly clean around the hydraulic hose connections to the pumps.5. Mark all the hydraulic hoses and electrical wires running to the pumps for identification when the pumps are reinstalled.6. Disconnect the hydraulic hoses from the pumps and immediately cap or plug all openings.7. Disconnect the electrical wires from the pumps.8. Thoroughly clean the areas where the pumps butt against the gearbox.9. Attach a lifting device to the conveyor drive pumps, the pumps weigh about 66 kg (146 pounds) total. Remove the mounting bolts, pull the pumps straight back from the gearbox until the shaft is clear of the gearbox, then move the pumps away.10. Repeat step 9 for the two remaining sets of pumps. The ground drive pump weighs about 82 kg (180 pounds). The vibrator pump and auxiliary pump weigh about 49 kg (109 pounds).11. Attach fabricated lifting lugs to the pump drive gearbox and attach a lifting device to the lifting lugs. Support the weight of the gearbox. The gearbox weighs about 104.5 kg (230 pounds).12. Remove all the bolts from the engine adapter, except the four at the top.13. WORKING FROM ABOVE THE PUMP DRIVE GEARBOX, turn the remaining four bolts alternately and evenly until the flywheel housing cover is free of the engine.
THE GEARBOX SHAFT MAY BIND IN THE DRIVE PLATE HUB THEN SUDDENLY BREAK LOOSE AND ALLOW THE GEARBOX TO SWING OUTWARD. PERSONAL INJURY COULD RESULT. DO NOT STAND NEAR THE GEARBOX.
14. Move the gearbox straight outboard from the engine until the shaft is free.15. If necessary, remove the drive plate from the flywheel.Disassembling The Pump Drive Gearbox
1. If the adapter sleeves stayed with the gearbox, remove them.2. Remove the input shaft, flywheel cover and input gear from the gearbox.3. Remove the pump adapter plates from the gearbox.4. Remove the drive gears from the gearbox. The gears will remain with their bearings as sub-assemblies.5. Remove the bearings from the gears with a puller.6. Inspect the case for cracks or other damage, especially around bolt holes and shoulders that support bearings.7. Clean and inspect gears for chipped, broken or cracked teeth or splines.8. Clean and inspect the bearings.Assembling The Pump Drive Gearbox
Reassemble in reverse order of disassembly. Turn the input shaft by hand to ensure that the unit is free running. (Any binding of bearings in housing bores will load the bearings endwise and cause excessive heat when running.) Use all new gaskets, seals and O-rings. Cover openings to keep dirt out of the gearbox.Installing The Pump Drive Gearbox
The operating lifetime of the gearbox depends a great deal on proper installation and initial startup. Misalignment between engine components and/or gearbox components can drastically reduce the life of the gearbox. It is, therefore, good practice to check the flywheel and flywheel housing runout before installing the gearbox. See Powerpack 4.0-8 for procedures to check the runnouts.
INADVERTENT STARTING OF THE ENGINE COULD CAUSE PERSONAL INJURY. STOP THE ENGINE AND REMOVE THE KEY FROM THE IGNITION SWITCH.
1. Install the drive plate.2. Attach a lifting device to the pump drive gearbox. The gearbox weighs approximately 104.5 kg (230 pounds).3. Move the gearbox into position at the rear of the engine. Align the splines on the input shaft with the splines on the drive plate, then move the gearbox until the flywheel cover is flush with the flywheel housing. Install the mounting bolts in the flywheel cover. 4. Attach a lifting device to the ground drive pump. The pump weighs approximately 78.6 kg (173 pounds).5. Move the pump into position near the gearbox, coat the pump shaft with noncorrosive grease, position the O-ring, insert the shaft into the gearbox, and install the mounting bolts.6. Repeat steps 1 through 3 for the vibrator pump and auxiliary pump assembly and then for the conveyor pumps assembly. The vibrator pump assembly weighs about 49 kg (109 pounds). The conveyor pump assembly weighs about 66 kg (146 pounds).7. Thoroughly clean around the pump ports and hydraulic hose ends, then connect the hoses to the pumps.8. Connect the electrical wires to the pumps.9. Loosen the supply hose connection at each pump until air-free hydraulic oil flows from the connection, then tighten the connection.
THE SUPPLY HOSE TO EACH PUMP MUST BE FILLED WITH HYDRAULIC OIL BEFORE STARTING THE ENGINE OR THE PUMP WILL BE DAMAGED.
10. Fill the pump cases through each uppermost case drain port with filtered hydraulic oil.11.