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8M0236271
842739T02
842739T04
842739T05
842739T08
842739T12
842739T06
842739T07
842739T14
842739T15
893680T05
8M0078253
8M0102481
8M0117246
8M0228066
8M0236239
9148A31
9148A76
9148A77
9148A86
9148A92
9148T86
9148T92
857113T3
859399R13
859399T18
859399R13
859399T13
9760A8
9760T23
8M0078254
8M0102484
8M0117249
8M0215264
8M0228054
8M0236233
8M0228609
842739T03
842739T16
880686T58
Mercury Racing Lower Unit and Gearcase
Mercury Racing 8M0176859 5.44 Inch XL Gearcase
Mercury Racing 8M0176859 is a 5.44 inch XL gearcase assembly with a 1.60 gear ratio and standard rotation. It is used on Mercury Racing 450R supercharged 4.6L V8 Verado platform applications.
This current Mercury Racing gearcase supersedes 8M0159651. Because complete lower unit assemblies are highly specific to shaft length, gear ratio, rotation, engine family, and serial number, confirm your exact application before ordering.
Compatible Applications
| Brand | Engine / System | Application | Fitment Note |
|---|---|---|---|
| Mercury Racing | 450R Supercharged 4.6L V8 | 5.44 inch XL gearcase, 1.60 ratio, standard rotation | Verify by serial number, shaft length, ratio, and rotation |
| Mercury Racing | High-Horsepower 4.6L V8 Performance Models | Select applications requiring XL shaft and 1.60 standard rotation gearcase | Confirm the OEM parts diagram for your engine serial number |
Important Fitment Note
Always confirm compatibility using your engine serial number, model, existing gearcase number, shaft length, gear ratio, and rotation before ordering. XL, counter rotation, standard rotation, and ratio differences are not interchangeable.
OEM & Cross Reference Numbers
| Current Mercury Racing OEM Number | 8M0176859 |
| Superseded From | 8M0159651 |
| Description | 5.44 inch XL gearcase, 1.60 ratio, standard rotation |
What This Part Is Used For
This is a complete lower unit gearcase assembly used to transfer engine power through the driveshaft and gear set to the propeller shaft. The 1.60 gear ratio and standard rotation configuration are designed for specific Mercury Racing performance setups.
Replacement may be required after gearcase impact damage, internal gear failure, bearing damage, housing damage, or a complete lower unit service decision where assembly replacement is preferred over rebuilding.
Key Features and Benefits
- Genuine Mercury Racing gearcase assembly
- Current part number 8M0176859
- Supersedes Mercury Racing 8M0159651
- 5.44 inch gearcase for high-performance applications
- XL shaft configuration
- 1.60 gear ratio with standard rotation
- Designed for select Mercury Racing 450R and 4.6L V8 performance models
- Best verified by serial number, shaft length, ratio, and rotation
FAQ
What does Mercury Racing 8M0176859 replace?
Mercury Racing 8M0176859 supersedes 8M0159651 for this 5.44 inch XL, 1.60 ratio, standard rotation gearcase application.
Does this fit the Mercury Racing 450R?
This gearcase is used on Mercury Racing 450R supercharged 4.6L V8 applications that require the XL shaft, 1.60 gear ratio, and standard rotation gearcase.
Is this the same as a counter rotation gearcase?
No. This page is for the standard rotation version. Counter rotation gearcases use different part numbers and must be matched to the correct engine and boat setup.
What should I verify before ordering?
Verify your engine serial number, shaft length, rotation, gear ratio, and current gearcase part number. Complete gearcase assemblies are application specific and should not be selected by horsepower alone.
Dealer Discounts & Store Policies
Dealer / Marine Industry Discounts
Are you a marine dealer, technician, boat builder, or industry professional? We offer dealer pricing for qualified marine businesses.
Shipping Policy
- Free shipping on orders over $100 continental U.S.
- Orders ship via UPS, USPS, and FedEx.
- Orders received before 5:30 PM EST ship the same business day.
- Typical delivery time is 1-5 business days.
30-Day Return Policy
- Returns accepted within 30 days of delivery.
- Parts must be new, unused, and in original packaging.
- Installed parts are not returnable.
- Return authorization is required before sending items back.
Need help with a return or order question?
Contact Us
Phone: 941-721-3000
Searchable Terms
Mercury Racing 450R gearcase, Mercury 450R lower unit, Mercury Racing XL gearcase, 5.44 inch gearcase, 1.60 ratio Mercury gearcase, Mercury standard rotation gearcase, Mercury V8 Racing lower unit, 450R standard rotation lower unit
Searchable Part Numbers
8M0176859, 8M0159651, Mercury Racing 8M0176859, Mercury Racing 8M0159651
8M0176859