Wow...good bit of miles luckily these motors last a good long while as long as you take care of them. The autohubs if they don't already, they'll end up not working right and you'll have to try and clean them good to see if they work properly after that or else you'll end up having to buy new auto's or replace them with good WARN manual hubs, the auto hubs engage after you drive the vehicle a couple inches with the 4X4 engaged. Another thing sometimes the shift motors on the t-case that engages the 4X4 may throw a fit if you don't use the 4X4 for an extended period of time, and usually tapping on it with a hammer will get it working again. The automatic tranny's in the 91-94 explorer's aren't favored too much because they're known to fail but if you don't do much towing and you keep them cool (best to have a tranny cooler) and change the fluid and filter when needed it should last ya awhile. These are great trucks though in my opinion, I love'em I had a 94 and 92 great 4X4's with manual hubs. Just a warning if you get in a stuck position with the auto hubs and you press the 4X4 when you get stuck you're not going to have much luck since you have to drive forward a little to get the auto's to engage and if you have it engaged already by the time you get stuck rocking it back and fourth won't help much either. Alot of us who had or has the 91-94 ex's with the auto hubs have replaced with manuals because they're more dependable and if you get stuck you can lock those hubs in and your in 4X4 unlike the autohubs. If having to lock the hubs all the time bothers you, you can lock them in and leave them locked in, it won't hurt the drivetrain. Thats some insight on the ex for ya. someone will prob. add more.