Some of the 03-04 Tahoes, etc. used to get water in the trans through the filler from a faulty design cowl drain. The water would eventually loosen the the bonding of the T/C clutch lining. Some were more severe than others. Never was there enough water in the fluid to show on the dipstick on the ones I had. You could only see a film on the bottom of the pan when removed and rusted valve body spacer plate.

Not saying that's what you have but I am saying the clutch in the T/C is kinda sensitive. In addition to possible T/C problems, there could be a sticking valve or debris in the valve body, a leaking TCC solenoid, or something a little off in the tune.