First you need to figure out what gears you truly have, either 3:27 or 3:73. 410Fortune explained how to do that, using the driveshafts, or you can count teeth on the ring gear.
33's on 3:27 is not a good combo for your hilly area. 3:73 is not optimal, but better. The right combo for keeping the engine in the stock power band is 4:56 with 33's. If it is 3:27, I would either change the tires to the stock 235's, or re-gear to at least 4:10 with the 33's. 4:10 ratio gears came stock in the Explorer and can be found used, for a simple axle swap for a few hundred bucks. 95-01 8.8's have disc brakes, and are a better setup if you did that. Front diff is a bit more involved to swap, but it is also a direct bolt in. Gear swap can cost upwards to $1k per axle at shops. Using stock axles, with you doing the work, can be done for less than $500 total. Cheaper if you really shop.
I highly doubt you have 12.5" wide wheels. Stock wheels are 7" wide, and most aftermarket wheels are from 8"-10" wide. A 12.5" wide tire can fit on those.
Are you turning the front axles or the front driveshaft? Both wheels off the ground?
As far as the hubs go... Both tires need to be off the ground when you spin them. Your front differential is open carrier (stock), and the wheels should spin in opposite directions if both axles are locked by the hubs. If only one wheel spins freely, both hubs are not locked. If the front drive shaft spins while turning a wheel, that hub is locked. If an auto hub is engaged when free spinning by hand, it is jammed. Auto hubs only engage when power is given from the transfercase to the front driveshaft. If the hub is broken, it can't transfer that power to the wheel, even if the front drive shaft is turning the gears.
My suggestion is to ditch the auto hubs, and swap to the manual hubs. These are stronger, and more reliable. You sacrifice being able to go into 4wd from a push of a button, as you have to get out, and lock the hubs manually, but it is a small sacrifice to make. There are how to write ups here for that easy swap.