I've been smelling hot gear oil and finally located the culprit. The input seal on the Adventure is leaking.
This one was installed back at 97,000 miles. Now, at 181,000 it's time for another. I'll be checking the bearings as long as I'm there.
This means the money I was going to use to buy tires goes to buy transmission parts. Maybe a clutch as long as I'm in there as it is the same age as the seal.
Oh, well another time.