Simpson Gear Set
WARNING: This page does not describe the selected car, but rather 212 other vehicles, including the 2012 BMW 750i, 2012 BMW 750Li, 2011 BMW M3, 2011 BMW 750i, and 2011 BMW 750Li. However, it is still accessible from the selected car via links, so may be relevant.
The Simpson Gear Set is one of the early variations on the simple set. It is capable of 3 forward gears and one reverse. On BMW transmissions, the Simpson Gear set is used in the 4HP transmission which is a four speed automatic. See Fig 1. Fourth gear (overdrive) is obtained by the addition of an auxiliary gear set (simple). Characteristics of the Simpson Gear set are as follows:
- Two Internal Ring Gears, one rear input ring and one attached to the rear planetary carrier.
- Two Planetary carriers, each containing three planetary pinions.
- One common Sun gear, which meshes with both sets of planetary pinions.