Transmission temp running hot?

Boat: 2007 Malibu Wakesetter VLX, Monsoon Engine 150hrs

Took the boat out sunday, and after 40 mi. of riding, got an alarm code. Come to find out if was the trans temp alarm. Check the fluid, was a little low, so headed back to the dock. Had to limp it back bc it started slipping a bit when try to run 20+ mph. Next day when back out to investigate problem, added some fluid to the correct level, after 40 min. of riding alarm came back out, fluid level was good. But no slippage this time. So i troubleshooted some issues, i ordered another impeller, although this one was changed last season, i took the heat exchanger off but it's all free and clear of debris. Could the internal pump on the transmission be out or plugged? Trying to troubleshoot all the little things before i move into something bigger like pull the tranny. Also the next day when we took it out, after the alarm came on, some of the fluid was spewing out of the bleed. I'm assuming that's just b/c of the temp. getting hot, it's causing pressure to build up and relieve out the bleed.