Blazer Forum - Chevy Blazer Forums - 99 Blazer 4x4 issues

OK so i bought a 99 blazer 4x4 with the 3 button 4 wheel drive. When i bought it the owner told me that the 4x4 had gotten stuck in 4 wheel drive so they cut the vacuum line that goes to the actuater and it came out. So i changed the actuater that is on top of the transfer case and hooked the vacuum line back up. Put it in neutral and put it in 4lo and it sure seems to work. I mean you can really tell that it is in 4lo. So being stupid one night i decided to take it off road. I pull off and stop and then put it in 4lo. I went about 10-20ft and then got stuck. Backed up a little but couldnt get out. I got out of the truck and had someone else trying to move the truck and noticed neither one of the front wheels were turning. I ended up getting it pushed out of the mud and tried to put it in 4lo again. Seems like it is working. The lights on the buttons are working properly. Do you have to move so much brfore the 4 wheel drive kicks in or what. Any ideas are greatly appreciated.