925

With the introduction of the more powerful 2.4 engines in the 1972 model year in the 911E and 911S, the 905 transmission was no longer strong enough to handle the increased torque from the larger displacement engines. A new Sportomatic transmission was introduced in there cars, the Type 925, which is based on the 915 manual transmission. The following differences can be noted:

• Larger diameter torque converter and clutch
• Larger crown wheel and pinion assembly
• Stronger differential

These changes allowed the torque capacity to be increased to 170lb/ft. This enabled the Sportomatic transmission to be made available on 1972 model year 911S versions for the first time since 1968.

Type 925/10
The four-speed 925 transmission remained in use for 1974 model year cars with K-Jetronic fuel injection, but with the introduction of the 1975 model year 911S, the torque output was considered too high for the four-speed Sportomatic transmission. For this car, transmission 925/10 was developed.

In light of the additional torque available from 2.7 litre engines, Porsche decided only 3-speeds were required in the Sportomatic gearbox, allowing the driver to make fewer gearshifts. Wider gears increased the torque capacity, while maintaining the external dimensions of the gearbox. This version uses an 8/27 crown wheel and pinion combination.

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More 925/10 technical information
925/00, 925/01, 925/02 differences
925/13, 925/16 differences