Methods of fabricating combination gear for stacked planetary gearset

A method of fabricating a combination gear for a stacked planetary gear assembly comprising the steps of:

• forming a first, ring gear having gear teeth on an inner surface,
• forming a second, sun gear having gear teeth on an outer surface,
• forming an annular projection on an end of said first, ring gear,
• forming an annular channel on an end of said second, sun gear,
• assembling said second, sun gear on said first, ring gear by engaging said projection and said recess, and
• electrically heating said projection and channel and bonding said first, ring gear to said second, sun gear.

A method of fabricating a combination gear for a stacked planetary gear assembly comprising the steps of:

• forming a first, ring gear having gear teeth on an inner surface,
• forming a shoulder adjacent an outer surface of said first, ring gear,
• forming at least one first mating feature on said first, ring gear,
• forming a second, sun gear having gear teeth on an outer surface and an end surface,
• forming at least one second mating feature complementary to said first mating feature on said second, sun gear, and
• assembling said second, sun gear on said first, ring gear by engaging said first and second mating features and abutting said end surface of said sun gear with said shoulder of said ring gear to axially offset said gears.