Cant find anything in manual about shifting from 2WD to 4WD. What is the proper procedure for doing this without harming machine?

 

What machine/model do you have?

 

as long as both front and rear tires are moving at the same speed, you're fine. But let's say youre in 2wd and your stuck and spinning the rear tires and the front tires are stopped or going really slow, when you engage 4wd the axles lock together, now whatever it is that locks your axles together will grind and clash from the speed difference.

But let's say you're in 2wd and cruising on a trail at 40mph, and you see a puddle up ahead, you can switch to 4wd because all your tires are moving at the same speed, so there is no speed difference between the front and rear axles.

also, if you're completely stopped on a trail you can go in to 4wd, that one's obvious.

 

sorry, I have a 06 foreman 500. so I can switch for 2wd to 4wd as long as both tires are moving at the same speed. 'Dont have to stop and put in neutral 4 wheel on the fly I quess.