Two technicians are discussing the Simpson gear set. Technician A says the front planetary ring gear and the common sun gear are the only two inputs. Technician B says the high and reverse clutch supplies rotational power to the sun gear when the clutch is applied. Who is correct?

Two technicians are discussing the Simpson gear set. Technician A says the front planetary ring gear and the common sun gear are the only two inputs. Technician B says the high and reverse clutch supplies rotational power to the sun gear when the clutch is applied. Who is correct?

• A. Technician A
• B. Technician B
• C. Both Technician A and Technician B
• D. Neither Technician A nor Technician B

Answer: (C)

In a Simpson gear set, two planetary gear trains share a common sun gear, so power can enter the system through more than one path. The front planetary’s ring gear can be driven by the input shaft, providing one route for power into the set. The sun gear is common to both planetary sets, and it can be driven directly when the high and reverse clutch is applied. That clutch connects power to the sun gear, making it an active input path as well. Because both of these paths supply rotational power into the Simpson gear arrangement, both technicians describe valid inputs.

In a Simpson gear set, two planetary gear trains share a common sun gear, so power can enter the system through more than one path. The front planetary’s ring gear can be driven by the input shaft, providing one route for power into the set.

The sun gear is common to both planetary sets, and it can be driven directly when the high and reverse clutch is applied. That clutch connects power to the sun gear, making it an active input path as well.

Because both of these paths supply rotational power into the Simpson gear arrangement, both technicians describe valid inputs.