I purchased the truck used with 98k now at 106k the transmission has failed. I am having it rebuilt ($5k... ouch) and was wondering if I could get some advice on preventative maintenance while it is torn down. I don't know if the radiator is the original or not so I will surely be replacing that. Any suggestions on what radiator to go with? I want to make sure that there is absolutely no chance for the coolant trans. fluid mixture problem. Thanks.