IF you are having your front wheels spinning faster than your rear wheels then the gearing in the differential is OFF, that doesn't have nothing to do with the transfer case. Transfer case distributes a 1:1 ratio, if it doesn't then somebody has/had switched it from what it should be. That is also the reason why they always claim to run the same size tires of the same brand and never swap new tires with old ones, to avoid the faster wheel spin either from the front or the rear. A person that may set up a a mud buggy and strickly a mud buggy will have the gears higher in the front so the front helps pull them through the mud better though.