2013 Durango V6. The other day I noticed a bit of oil under the front bumper. Upon inspection I noticed that it was coming from the transmission oil cooler. Since these vehicles come without a Dipstick to check the ATF, I purchased a universal one on Amazon. The other day I use the dipstick to check the ATF and it measured on 30mm on the dipstick. I will be replacing the Tranny cooler this weekend and I would like to ask of anyone can tell me about how much ATF, I would need to add so it will be back up to normal levels?