Gear ratio will be on window sticker or you can google jeep vin lookup and you can get the build sheet. If you still can't find it send me vin
And yes on hard surfaces steering in 4wd will be harder as the axles bind up since they have to travel at different speeds is a corner. Only AWD vehicles have a center differential so axles don't bind
Try not to do it on pavement, unless it's slick.
IF when after taking it out of 4wd it still feels like it's binding, turn strg wheel back and forth while rolling slowly, worst case roll forward at 5 mph or less, put trans in reverse and blip the throttle... DON"T slam it to floor. Preferably on grass or sand
4hi is for slick running like snow or ice
Real off road use 4 lo, your transmission will thank you
Were you taught the proper way to shift the transfer case on a JK? 2hi to 4hi can do at any speed as long as neither axle is slipping, 4hi to 4lo roll forward about 5mph, slip trans into N (or push clutch in) and PULL on lever, don't snatch on it... There's a crappy plastic bushing that holds transfer case shift cable to case lever. Gears may grind a bit
Join your local Jeep club, they're a wealth of knowledge and sometimes they throw wrenching parties to install other's goodies.