Losmandy's New Gearbox 
Losmandy has modified the gearboxes to make the stronger.  They have replaced the plastic dimples with metal rivets that extend all the way through the gearboxes to hold them together.

Motor side of Gearboxes.
New Gearbox is on left, Old gearbox in on right side.

Worm side of Gearboxes.
New Gearbox is on left, Old gearbox in on right side.
Pictures courtesy of John Grant