EXPLODED PARTS DIAGRAM
MerCruiser Alpha One Gen II Upper Driveshaft Housing Parts Diagram, 0L100040+
Parts schedule
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Related diagrams and guides
Alpha One Gen II upper housing parts in this diagram
This diagram covers the upper driveshaft housing, top cover, vertical drive shaft, upper gear sets, roller bearings, shims, oil seals, U-joint components, water-guide parts, wear pads, fasteners and anode options. It does not cover the lower gear housing, propeller shaft, water pump or transom assembly.
Choose the upper gear set by ratio
Callout 7 contains alternative gear sets for different drive ratios and tooth-count combinations. Callout 8 also changes by ratio. Confirm the drive's actual ratio and match the scheduled reference. Do not select a gear set or bearing from appearance alone.
Check the 0M400411 and 0M400412 production change
Several oil-seal and U-joint components change around serial 0M400411 and 0M400412. Match the full serial number to the note on the relevant schedule row before selecting the yoke, U-joint, centre socket or related seal.
Seals, bearings and shims are selection parts
Shims set gear and bearing position, while ratio-specific gears and bearings must remain correctly paired. Individual seals are listed separately from seal kits. The diagram identifies the parts but does not replace the workshop measurements, preload settings or torque procedure required for a rebuild.
Anode choices for the Alpha One Gen II
The schedule includes separate housing and kit options in zinc, aluminium and magnesium. Select the material for the operating water and the vessel's existing corrosion-control system. Do not mix anode materials without checking the complete protection strategy.
How to use the diagram and parts schedule
- Confirm that the equipment is MerCruiser Alpha One Gen II / OL100040+ (1998+) and check any page-level year or serial scope.
- Find the required component on the exploded drawing and note its numbered callout.
- Match the callout to the product code and OEM cross-reference in the parts schedule.
- Apply every model, serial, ratio, side, material and configuration note shown for that row.
- Compare the selected replacement with the removed part before installation.
Fitment and cross-reference checks
The page-level route is MerCruiser Alpha One Gen II / OL100040+ (1998+). It helps customers reach the correct drawing, but it does not make every product in the schedule interchangeable across every version of that model family.
An OEM number is an identification cross-reference. Confirm the exact product code, model designation and any bounded selection information before ordering. A product may also appear under another make or model only where that separate SKU-to-application fitment is independently supported.
Frequently asked questions
Which parts are shown on this MerCruiser ALPHA ONE GEN II / OL100040+ (1998+) diagram?
Does this diagram confirm fitment for every MerCruiser ALPHA ONE GEN II / OL100040+ (1998+) version?
How should I use the diagram number and OEM cross-reference?
How do I distinguish between alternative gears, shafts, bearings and seals?
What information should I provide if I need help identifying a part?
Identify upper driveshaft housing, upper gear, bearing, seal and U-joint parts for MerCruiser Alpha One Gen II sterndrives from serial 0L100040, 1998 onwards. Match the numbered callout to the parts schedule, then check every ratio and serial-break note.
Alpha One Gen II upper housing parts in this diagram
This diagram covers the upper driveshaft housing, top cover, vertical drive shaft, upper gear sets, roller bearings, shims, oil seals, U-joint components, water-guide parts, wear pads, fasteners and anode options. It does not cover the lower gear housing, propeller shaft, water pump or transom assembly.
Choose the upper gear set by ratio
Callout 7 contains alternative gear sets for different drive ratios and tooth-count combinations. Callout 8 also changes by ratio. Confirm the drive's actual ratio and match the scheduled reference. Do not select a gear set or bearing from appearance alone.
Check the 0M400411 and 0M400412 production change
Several oil-seal and U-joint components change around serial 0M400411 and 0M400412. Match the full serial number to the note on the relevant schedule row before selecting the yoke, U-joint, centre socket or related seal.
Seals, bearings and shims are selection parts
Shims set gear and bearing position, while ratio-specific gears and bearings must remain correctly paired. Individual seals are listed separately from seal kits. The diagram identifies the parts but does not replace the workshop measurements, preload settings or torque procedure required for a rebuild.
Anode choices for the Alpha One Gen II
The schedule includes separate housing and kit options in zinc, aluminium and magnesium. Select the material for the operating water and the vessel's existing corrosion-control system. Do not mix anode materials without checking the complete protection strategy.
How to use the diagram and parts schedule
- Confirm that the equipment is MerCruiser Alpha One Gen II / OL100040+ (1998+) and check any page-level year or serial scope.
- Find the required component on the exploded drawing and note its numbered callout.
- Match the callout to the product code and OEM cross-reference in the parts schedule.
- Apply every model, serial, ratio, side, material and configuration note shown for that row.
- Compare the selected replacement with the removed part before installation.
Fitment and cross-reference checks
The page-level route is MerCruiser Alpha One Gen II / OL100040+ (1998+). It helps customers reach the correct drawing, but it does not make every product in the schedule interchangeable across every version of that model family.
An OEM number is an identification cross-reference. Confirm the exact product code, model designation and any bounded selection information before ordering. A product may also appear under another make or model only where that separate SKU-to-application fitment is independently supported.
Frequently asked questions
Which parts are shown on this MerCruiser ALPHA ONE GEN II / OL100040+ (1998+) diagram?
This MerCruiser ALPHA ONE GEN II / OL100040+ (1998+) page covers valve, drive shaft, gear, bearing, oil seal, O-ring, anode within the gearcase gears, shafts and seals drawing. Use the callout position to identify the required assembly before choosing a product.
Does this diagram confirm fitment for every MerCruiser ALPHA ONE GEN II / OL100040+ (1998+) version?
No. This gearcase gears, shafts and seals diagram establishes the MerCruiser ALPHA ONE GEN II / OL100040+ (1998+) page application, but it does not make every scheduled product interchangeable across every version. The printed page-level boundary is 0L100040+ (1998+). Product-level notes can narrow that scope further, so check the selected schedule row as well.
How should I use the diagram number and OEM cross-reference?
Find the gearcase gears, shafts and seals part on the MerCruiser ALPHA ONE GEN II / OL100040+ (1998+) drawing, match its callout to the schedule, then confirm the supplier reference and OEM cross-reference. The OEM number helps identify the part, but the selected row's application notes still control fitment.
How do I distinguish between alternative gears, shafts, bearings and seals?
For MerCruiser ALPHA ONE GEN II / OL100040+ (1998+), use the exact callout row and product reference, then apply every ratio, rotation, shaft-length, material, year and serial note printed for that row. Similar appearance or horsepower alone is not enough.
What information should I provide if I need help identifying a part?
Provide the full MerCruiser ALPHA ONE GEN II / OL100040+ (1998+) model, serial number where available, the gearcase gears, shafts and seals diagram callout, the printed product or OEM reference and a clear photo of the removed part or identification plate.
