Usage:
All 7200 Series Marine Transmissions
Description of Change: A new ahead main shaft assembly with a larger shaft diameter is now used on 7251 (74E2392-up) and 7261 (89B718-up) Marine Transmissions. This larger diameter shaft will give a tighter fit between the shaft and the gear. This will prevent corrosion caused by fretting (movement of metal).
Adaptable To: The new 3T3455 Shaft Assembly is a direct replacement for the former 4L4351 Shaft Assembly which is canceled. The diameter of the shaft assemblies in 7231, 7241, 7251 and 7261 Transmissions also changed, but the part number did not change.
The dimensions for the shafts and gears are shown in the chart.
INSTALLATION: All gears must be heated to a maximum temperature of 177°C (350°F) before they are installed on the shafts.
The gears when heated correctly will slide freely onto the shafts. To correctly heat the gears they must be heated in oil or in an oven. Do not use a torch to heat the gears, because the gears can not be heated evenly. It is possible to over heat the gear in some locations with a torch. This can change the heat treatment of the gear.
