Belt squeal/chrip noise.

[Jackpine]

I feel certain it's the belt. I have the same thing, on the 2-3 upshift. Bill has altered the torque reduction, line pressures and clutch engagement delays, so there's a bit of a "hard" engagement there. The engine's spinning high before the shift and then the transmission drags it down abruptly. All the other "spinning things" have to slow down abruptly too and something "slips".

I doubt it hurts anything, but if you are bothered by it, the Gatorback belt has been recommended as a cure. I also imagine Bill could "tune" thins belt slip out. I don't feel either are needed.

- Jack