My tranny slips some times but it will catch after a few min

SOUND LIKE TRANSMISSION FLUID LOW OR YOU NEED A TRANSMISSION FLUID AND FILTER CHANGE.THE 4T40E OR 4T45E IF YOU DONT SEE TRANSMISSION DIP STICK.BEST TO DO A FILTER AND FLUID CHANGE.YOU NEED 7 QUARTS OF TRANSMISSION FLUID A NEW TRANSMISSION FILTER AND PAN GASKET.I WOULD BUY FILTER AND PAN GASKET AT DEALERSHIP.YOU NEED A LARGE DRAIN PAN TO CATCH TRANSMISSION FLUID.IF YOU HAVE A TRANSMISSION DIP STICK. BEFORE YOU FIRST BEFORE STARTING THE ENGINE CHECK TRANSMISSION FLUID LEVEL ON DIP STICK.SHOULD BE ON THE FULL MARK.IF NOT ADD FLUID TO FULL MARK.THEN CRANK VECHICLE LET IDLE UNTIL ENGINE HOT OPERATION TEMPERATURE ABOUT 10 MINUTES.THEN APPLY BRAKE PEDAL.THEN SLOWLY SHIFT TRANSMISSION SHIFTER THROUGH ALL GEARS 2 TIMES.THEN PUT TRANSMISSION IN PARK.CHECK TRANSMISSION FLUID LEVEL.IF NOT AT FULL MARK ADD TRANSMISSION FLUID UNTIL LEVEL CORRECT.