Usage:
7251 Marine Transmissions (3.24:1 Ratio)
Reference: Engine News, July 9, 1980, Pages 3 and 4. The article, "New Planetary Group Has Gears Which Operate With Lower Noise Levels," tells about the use of the three new gears to decrease the amount of noise from 7251 Marine Transmissions with a ratio of 3.95:1. This change has now been made for the 3.24:1 ratio.
Description of Change: In some applications, the noise levels of 7251 Marine Transmissions with a 3.24:1 ratio have not been acceptable. For this reason, a new planetary group with three new gears are used. The new gears have a different number of teeth, and the ratio changed to 3.25:1. The number of teeth used now gives a different sequence of tooth contact during operation, with a better distribution of tooth loads between the gears. The result is a much lower noise level in the gear group.
Adaptable As: The new parts, when used together, are direct replacements for the former parts as shown in the chart. The new parts are in effect with Serial Number 74E2414.
