4x4 not workin PLEASE HELP!!!!!
 

:icon_cankick:just got the first snow of the year so I went out to see if my 4-wheel drive was working and nothing happend now I know it's bad but could it be because I got 31's on the back and 235's on the front or were should I start to look for a problem the lights on the dash are working fine I don't have a clue were to start please help

I can hear the transfer case switch over so what I'm thinking is because I got smaller tires on the front the axles don't spin at the same speed so it's kickin out and wont engage ...is my theory correct ..because before I changed the fronts I had all 31's on and it worked fine

Put it this way.. if that's not the problem, you cant find the real cause until you do get same size all the way around. And you dont want to, for that matter. Because you'd put a lot of wear and strain on the transfer case.
WHat did you think would happen?

buddy you gotta have same size tires to even start looking for the problem. different size tires could even BE the problem here. DO NOT try to drive in 4wd with different size tires on the blazer, these cars HATE IT. I know cuz I did the same thing and was also having terrible issues with 4x4.

put same size tires on first, and then if your 4x4 still acts up come back in here.

As stated, you MUST have the same size tires on the front and back of the truck or risk serious mechanical damage to the drivetrain. Depending on the tire size, you could have 2" of height difference (31's vs 235/75R15 w/ ~29" OD) or 3" of height difference (31's vs 235/70R15 w/ ~28" OD). Either of which is a significant difference and will cause the drivetrain to bind even on low traction surfaces. Basically, the end with the larger tires wants to go faster than the end with the smaller tires due to the decreased revs/mile ratio of the larger tires. When in 4wd, the front and rear driveshafts are locked together and must turn at the same speed. Different tire sizes will have different shaft speeds for a given ground speed which the system is not capable of allowing.

Hopefully you haven't already destroyed something in your drivetrain.