I heard back from the dealer today (dealer #2). They said nothing was wrong with the transmission (no surprise), but that they surely saw what was going on and, at first, couldn't figure out why it was happening. "It just didn't have any power."
Then they changed my brand new high lift blades out with standard blades and say that it was like adding 10HP. So they're now pointing the finger at the blades that dealer #1 recommended that I get after asking me if I have tall or thick grass. (Well, YEAH...it's been raining non-stop this summer!)
Dealer #2 went on about these blades creating a high vacuum or something. And also said that I should be using the standard or low lift blades anyway because I have sandy soil which tears up the blades. (The original blades lasted 100 hours.)
Does any of this make sense to anybody? They swear it's running great now and they can't make it overheat or bog down.
Bill