Check under DIY tech. Check to that when you have it engaged, trans in park , reach under front and see if the front drive shaft turns. Could be you have no vacuum going to the front actuator that pulls the cable to engage the front axles. The tech story will pretty much explain about all the problems and fixes.

 

I had a similar (and quite embarrassing) issue the other day. I was driving down a backroad in the country, the road was an ice rink. I slowly slipped off the road onto the gravel shoulder. I thought this was my lucky break, so I engaged my 4wd high. Heard all the appropriate clicks and clunks, went to get out...and the two right side tires spun. The same two right tires that were on the ice. Mind you, the two left were in gravel and snow...why would the tires on the slipperiest surface engage?? Long story short...I went absolutely nowhere. Tried the 4 low, same thing, except both rear wheels tried to go, front right engaged, left front didn't. It appeared to the other motorists that I just decided to park on the side of the road...I had sedans cruising by looking at me funny. Pride took a hit, and I had to walk home 3 miles with 60lbs of gear. I never want this to happen again. Anybody have any leads?

 

Had the same issue. If ya can, get it up on 4 jack stands. Start it and put it in drive and 2hi. Engage 4 hi with wheels rolling. Now listen....hear a faint clicking noise from front diffy? Its your pass side axle carrier gear, it destroyed. I spent less time and money pulling that axle off to fix that gear than i did dickin around with vacuum and other crap so its not a huge problem to fix. Theres a some videos on the fix on you tube. I attached a pic of the gear on another post. Napa sells the repair kit for about 100 bucks. Good luck! TK.

 

My Son's 2K S10 Blazer also had the clicking front axle.
The axle gear is stripped. I guess this happens quite often with this model. The Vacuum valve on transfer case was also leaking, and I replaced the vacuum line going to that valve. Actuator cable is free.
There is the slider gear that slides left or right depending on you are in 2 or 4 wd. With a funky vacuum,, the slider gear may not engage properly,, there by grinding the teeth off the axle gear. I got a new gear kit,,, my only ? is the two thrust washers,,,, [#5] none came out when I dismantled this,,,, unless they are in front gear case ????? So,, where do the #5 spacers go ???

 

I also noticed two in the kit and only one in the axle, I assume this may be for lash adjustment or end play on the axle, I mic'd the washers, found they were damn close in thickness, and only replaced mine with the one washer as it was. No issues thus far!

 

Forgot to mention, the thrust washer in my assembly was the last piece out, it was against the inside of the diffy housing. Last out first in.

 

ok,,thanks, I will look and see if a spacer is inside the differential ,,,,, still sorta' mysterious,, as two come in the kit ?

 

Having the same issue on my 98 I have 2wd and will go in 4lo no lights yet will not go in 4hi its snowing like crazy here and I drive 45 min to work 2nd shift tough with no 4hi and even with new tires she's still a little dicey in 2wheel.

 

Damn Sandman that sucks sorry to hear yeah I dont want that to happen to me or anyone for that matter

 

jbro,,,, are you certain it is going into 4w low,,,,,,,,,,,,,,,, or is it possible it is just 2w low,,,
if you front axle is not engaging,,, the transmission / transfer case may go into low and high,,, but the front axle is not engaging you are just in 2w low.

So, I got the above gear kit,,,,,, are you suppose to press the gear on to axle shaft,,,, it is pretty tight ????