@patdale thanks for saving me a bundle!
well, a couple hours after starting, things seem to be working just right.
I adjusted the balance of the door, which admittedly was probably the contributing factor to the failure.
it had been in operation for about a year since I put insulation on the doors.. the opener worked, so what could happen?
the kit was relatively easy to install, basic set of tools should cover it.
I replaced everything the kit provided, except the roll pin on the motor shaft.
two things not covered by the instructions, where some of the videos will help,
is that (1) the cover plate with the gear, for the chain; the holes are not tapped.. do it before hand;
or, you can just put in two screws from below, remove them, rotate the plate and do the remaining hole.
...and (2) make sure you rotate that same plate to where the sprocket cover slots line up properly