1992 GMC Jimmy 4 wheel drive engage

First. This car was probably bought completely stock.
replaced vacuum actuator under battery and vacuum switch on transfer case.
also realized that the thin vaccum line coming off engine (that seems to run everything)was apparently knocked off at one point that has been fixed.

before all the new parts and putting the hose back on, 4 wheel had a problem engaging. When it did it was spot on but to stop in one and shift to another sometimes did not work.

Question(s):
-Does this car need to be rolled backwards a hair to engage 4 wheel? That sounds weird.
-if the 4 wheel STILL does not engage properly 100% what else could be the problem(the thing that the vacuum actuator actually pulls to lock the front diffs? That is screwed into front case)
-you feel the car in 4 low. Barely moves feel the power. On this vehicle is there a power transfer to the wheels on the front as to give the illusion of the front and back tires spinning at different speeds? Depending on traction.
do I assume that if I lifted this car and put it into 4 wheel all the tires would move at the exact same speed.

ty