[RC-Monster Mike]

Here is another thing that has happened to me: If you look inside the tranny, it may first appear as if the gears are in good condition. What can happen, though, is the drive dog "nubs" will wear out, as well as the area on the gear that the drive dog "nubs" fit into. It will act exactly like you are describing. It would also make sense, because you had a perfect run somewhere in the middle. Perhaps if the tension is not quite right on the drive dog, it allows the nubs to slip inside the output gear. this recently happened to me happened to me, and I thought the gears were stripped until I looked a little closer at these items. I know you aren't thrilled about taking the tranny apart again, but you may want to check this out.