On the 1st door, the one that I had replaced the gear assembly, I also replaced both springs, and moved up in the spring load. The door moves up and down easily by hand, and will stay in place about half-way. These are 9x7 wood doors and are pretty heavy.
I went ahead and replaced that one with a Chamberlain Whisper Drive (Belt) and it working OK. I removed the cover the other day to observe the gear and it looks good so far. The internals and some of the parts look almost exactly like the Craftsman. Imagine that.
I got a good deal from HD and it had 2 remotes, a keypad, and even a lamp controller for use in the house. Even has a motion sensor so the light comes on when you walk into the garage. Nice when going to the fridge for a cold one.
Thanks for the input and we'll see how this one performs before I replace the 2nd one. That side is mostly storage anyway.