I have a Kenmore 417.98702890 stack unit that is acting up. The tub does not move counter to the agitator any more. As a result, water sloshes over the side when washing a full load. I believe it is a belt issue as the clothes do not seem to spin out as well as they did. The machine is nearly 12 years old. It cycles, fills, and empties properly. The tub spins freely in both directions (by hand) when the machine is off. It didn't do that before. Since there is no "brake" in the assembly, i can only assume that the belt is loose since that is the only thing that would inhibit manual tub rotation in the "wrong" direction. Am I crazy, thinking wishfully, or has the meager experience I DO have put me on the right track?