Ok, I'll admit my ignorance here since this is the first 4WD non ATV vehicle I've owned.

What is the proper procedure for shifting from 4WD Hi to 4WD low using the quadra trac shifter? I put the transmission shifter into N and shifted down to 4WD low but got a bit of a grinding sound so I stopped, tried again with a bit more force and got it into lo, same procedure for putting it pack into hi but got the same bit of a grinding sound when shifting forward. Is this normal or am I not shifting it properly?

When I'm in 4WD lo(via quadra trac shifter) are the front wheels locked?

sounds to me like the t case shifter isn't adjusted right or something.

Make sure that you have fluid in t case. You my try to adjust linkage.

no more than 2mph while shifting to and from 4 low. also neutral on the tranny to do so.
it's better to do while stopped.