So is it better to go higher like 4:70's etc,. 4:89's?
31's isn't that big tire size.
31s will be fine. I run 31s on 15x8 steel rims, stock 4.10:1 gears. My worn out 300,000 mile 22R did pretty good until it overheated to death trying to bump stuff with no lockers
I think you're mixing in transfer case gears. stock transfer case gears are 2.28:1 but a common upgrade is 4.70:1. The low range transfer case gears only matter when you're in low range. For your use, the stock 2.28 gears are perfect so don't worry about 2.28:1 vs 4.70:1
Common Toyota axle gears are 3.90:1, 4.10:1, 4.30:1, 4.56:1, 4.88:1, 5.28:1, and 5.71:1. Here is an excerpt from the Marlin Crawler store, on the ring and pinion page.
"Looking to change your Ring & Pinion ratio & are unsure what to use? Factors include how much stop-and-go, flat highway, or mountain use your truck sees. In generally, 33" tires go well with 4.56:1 or 4.88:1, 35" tires go well with 4.88:1 or 5.29:1, and 37" tires or larger go well with 5.29:1. We do carry a 5.71:1 ratio for certain applications, however it is weak and is typically not recommended."
How worn out is your engine? How responsive do you like your truck? If you really wanted to, you could regear to 4.56:1 but it shouldn't be necessary.
As for lockers, lockers are good. They have pretty hefty buy ins, but they can be well worth it. If you want to run ARB lockers, you'd have to invest and plumb onboard air. If you wanted to run Toyota electric lockers, you'd have to modify the axle housing. Auto lockers don't require anything special. They lock up when torque is applied, which can make cornering and parking lot driving a bit awkward but you would learn to "drive with the throttle". If you're just doing fire road driving you don't really need a locker, but I'll say with a decent offroad tire and a locker, these toyotas turn into scrappy little mountain goats.
