my van has not had any water leaks up front. as for transmission maintenance. i bought the dorman pan for a mazda with drain plug. i use atf mercon LV. i drain every 25k miles and refill with 4 quarts. at 50k miles i drain and change filter. i use these cool 3rd hand gaskets and squirt a tube of shudderfix, . i bought this one used, it had about 300k on it and motor and transmission had been replaced about 3 years before i got it. that guy was a city delivery and im a long distance delivery. my heater is the smaller one with remote. i use the bigger ones in my promaster and after getting one with remote wont do it any other way. i travel with a dog so i can just turn on the heater if i go inside to do a delivery. that keeps van warm enough. i have a maxxair fan but really thinking i want an ac.