i have a 1984 chevy k5 blazer 4x4 but the guy i bought it frm swapped out the differentials so now the 4x4 dont work right. i need to know what the correct dif's are that need to be put back in there.it has a posi track rear end rightnow..help is much appreciated

-KEEP BLAZIN!!!

 

i dont understand how the 4x4 wont work because of the diffs, unless it is a factory full time truck, it may be the transfercase

 

Were the hole houseings changed or just the gears? My 84 had self locking hubs, could be hubs not engaging. If they changed the gears and the front and rear are not the same ratio, would be a problem. Need more info.