Usage:
7231 And 7241 Marine Transmissions
Description of Change: New spacers and washers (locks) are used in the main (top) shaft groups on 7231 and 7241 Marine Transmissions. The new spacers are made of a hardened material so they will not be damaged when they are assembled with the new procedure.
The new washers (locks) are made to be used with tapered bearings. The use of the former washers (locks) in this application was not correct.
The new assembly procedure permits the parts to make complete contact with each other. Formerly, complete contact was not made when the parts were assembled. This made it possible for the retainer nut to loosen.
Adaptable To: The new parts are direct replacements for the former parts as shown in the chart.
Assembly Procedure For Main (Top) Shaft
Use this information in addition to the existing information in the Service Manual. The forward drive shaft must be assembled and installed on the reverse drive shaft, before the reverse drive shaft is assembled.
1. Heat the gears and bearings to a maximum temperature of 177°C (350°F). The temperature of the shafts can be lowered if it is necessary.
2. Put the roller bearings in position on the shafts.
3. Install the gear on the forward drive shaft.
4. Install the spacer and tapered bearings. Lower the temperature of the assembly to normal temperature before Step 5.
5. Push the bearings and gear in position on the forward drive shaft with a force of 90 ± 13 kN (18,000 ± 3000 lb) for the 7231 and 148 ± 22 kN (33,000 ± 5000 lb) for the 7241.
6. Put 5P3931 Anti-Seize Compound on the threads of the nut. Install the spacer, washer (lock) and nut. Tighten the nut to a minimum of 680 N·m (500 lb ft).
7. Put the forward drive shaft in position on the reverse shaft. Install the gear, spacer and tapered bearings on the reverse shaft.
8. Lower the temperature of the assembly to normal temperature before Step 9.
9. Push the bearings and gear into position on the reverse shaft with a force of 225 ± 22 kN (50,000 ± 5000 lb) for the 7231 and 355 ± 36 kN (80,000 ± 8,000 lb) for the 7241.
10. Install the spacer on the 7231. Put anti-seize compound on the threads of the nut.
11. Install the washer (lock) and nut. Tighten the nut to a minimum torque of 680 N·m (500 lb ft).
Location of new parts in main shaft group.