Planetary gear drive assembly

A method of assembling a planetary gear drive assembly of the type having a drive housing that includes an internal ring gear located on an inner diameter of the drive housing, a planetary gear train located within the drive housing, wherein the planetary gear train includes at least one planetary gear stage comprising a central sun gear and a plurality of planetary gears spaced around and in engagement with an outer diameter of the sun gear such that rotation of the sun gear rotates the planetary gears, each planetary gear further being in engagement with the internal ring gear on the drive housing when assembled, which includes the steps of:

• (a) providing alignment means extending in advance of the ring gear from a forward edge thereof, wherein the alignment means forms a continuation of the ring gear only over a circumferential portion of the ring gear such that the alignment means will first contact only one of the planetary gears in the gear stage before any of the other planetary gears in the gear stage encounter the ring gear;
• and
• (b) inserting at least one gear stage down into the housing such that the one of the planetary gears in the gear stage engages the alignment means before the other planetary gears of the gear stage engage the forward edge of the ring gear to self align all the planetary gears with the ring gear and ensure proper assembly.