Mine is a 1995 model, lift a latch on the axle, slide it over and engage the lower gearing and keep cranking ... Keep it greased and it works great 27 years later..
The longer handle will give you more leverage if you're shoulder can tolerate the larger turning circle. I don't use my trailer often but the 2 speed really helps alot particularly at the shallow ramp that I like to use. (Close to home)..
You'll find some folks that do feed 5 gals of anti-freeze thru the muffs at idle and get away with it but it's not fool proof. If the thermostat doesn't open you will have a busted engine but your manifolds will still be ok to use on your next new engine...
I feel your pain as my engine is...