I plan on using the Auto-Rx soon on the trans so you can use it on engine oil cleaning also? I am not stuck to 3,000 mile oil changes heck i remember when I use to do 7,000 and then 5,000 mile oil changes when i was young on a 87 toyota pickup with the 4clinder 22r engine and used 20-50 in it. Later went to 10 50 in the wenter. We used a lot of toyota oil filters then and when high mileage kicked in then we did 5000 mile oil changes. I personally don't like 10 30 for what its intened for as I know thats how most drive in those conditions. That truck then was getting a lot of highway miles back then. The bronco is going to be high and around town and off road vehicle. It won't be driven a lot anyway and not stop and goes day in day out either. Recreational vehicle,lol. I like to try synthetics but don't want to blow money either but I really don't want to go past 7,000 mile oil changes either. I am thinking on like 5000 or 7000 mile oil changes. Oil filters longs it don't make my truck run worse I don't mind spending 10.00 a filter on if I have to. As far as synthetic in other stuff for the truck i like to try also. I'm not crazy about spending that much on atf though so think on atf I will stay with reg atf not synthetic and everything else I will try. I got to change axle fluids soon anyway. I like to get idea setup when i do my next oil change also what I want to use. All I got her locally is a napa, o'rielly, and autozone. I do have a oil change place that carries amsoil oil and believe gear oil. I am not sure if to stick with stock weight or try the 80/140 weight gear oil. I don't have limited slip or lockers yet.