Mercruiser Upper Gearcase R/MR/Alpha One 1.98 Gearset 43-55778A3 120hp 140hp
Fast & Free Shipping on All Orders!
14-Day Return Policy
- All 120hp 2.5L & 140hp 3.0L 4cyl applications for Pre-Alpha/R/MR/ALPHA ONE Gen I, so 1970-1990 as a general rule.
The gear set here is 43-55766 & 43-55778A3 (Sierra equivalent 18-2205) (Also Equivalent to 43-55766A2 / 43-55766A3 as indicated in earlier parts manuals)
- 20-24 (tooth count) 1.98 Ratio for 4-cylinder GM Chevy 120hp 2.5L 151CID/ 140hp 3.0L 181CID 4-cyl Sterndrive engines.
- Upper Driveshaft Assembly 45-55797
- Races for driveshaft gears are not included you will receive exactly what you see in the pictures.)
- More parts here then I care to list, this is pretty much the major parts to replace the innards of Pre-Alpha/R/MR/Alpha One Upper gear housing.
- The existing bearings are probably fine, but please inspect bearings beforehand to make sure they are to your liking as your races may be different than the bearings here, its always recommended to start with fresh bearings & races when performing this type of service work, but this is ultimately up to your discretion.
- The seals in the carrier assembly should also be replaced, just purchase a complete seal kit for your outdrive.
- There is some pitting on one of the gears (see pictures) nothing that will affect function.
- If you have any questions on compatibility, or any other questions about this item, please don't hesitate to contact me.
- Freshwater Used Parts.
- Removed from a completely functional upper gearcase.
- Purchase with confidence!
1970 1971 1972 1973 1974 1975 1976 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990