Transmission on 03 Sienna



I have an 2003 Sienna with an auto transmissions that is slow to change gears from 2nd to 3rd only when it’s cold (which is often here in Maine). If I let it warm up on very cold days, I don’t have a problem but otherwise it really struggles making it out of second. I’ve had the fluid changed but it didn’t make a difference. Is my transmission shot with only 52k miles on it?