Howdy, all! I've been towing my 40' fifth wheel with this truck for about 3 years. Shifts are typically a little harder than when not towing. But yesterday, I noticed a REALLY stiff shift from 2nd to 3rd gear upon acceleration. Though I didn't chronicle the exact circumstances, I want to say it shifted at a higher RPM than usual. At the same time, I hear a sort of quick "swoosh" sound but a little metallic. It's hard to describe. The truck runs perfectly without the load. Shifts and TC lockup all as expected and smooth.Any ideas? This is an '02 with 230k miles and I bought it used at 195k. It's got a Garrett 38 turbo and an Edge Commander. The Edge is set to setting 1 "tow". Again, never had such a hard shifting before.