possible trans concern

my 99 tahoe 4l60e trans 5.7r engine,when i was going to get on the gas today when it upshifted it barely got up any faster than cruising speed,but engine noise kept rising rpm's didnt shoot up real fast to much but mph kept rising,in florida 93 degrees some traffic i was sitting in.not sure what it may be.some suggestions or somebody maybe had similar problem?

Check fluid level with engine up to temp and truck on level ground with trans in neutral. Look for foaming pink appearance to the fluid.