2000gp trans whine????

i have a 2000 gp with 67000 mile. i as summer came along it seems the tranny starts whining as it gets hotter. i checked the fluid the level is
good but looks a little dark and little bubbles a little foamy mabey .should i just have the filter and fluid changed or is it something else

I'd try fluid/filter first...if the fluid is dark, then it needs to be replaced. Actually, now, they've got a machine that cleans it and puts it back in...had mine done yesterday, and it noticeably cleaned up my shifts.