Alright, come on you S10 guys!  I have a 93 S10 blazer with push button 4wd.  When I push the button in for the 4wd I hear a clunk (the transfer case, right?) but the front wheels stay freewheeling.  The front driveshaft is turning, but the differential must not be enagaed.  Help me please!   Thank you very much!  

hey man had the same problem on a 95 s10 blazer.  check the vacuum actuator under the battery.  the actuator is what engages the front differantial.  costs about $70 at the dealer.  

Hey, thanks a lot for the help!  This sounds like a good place to start.  The truck belongs to my brother and he's away at college but we'll check when he gets back.  How do you go about getting to the vacuum actuator?  Is it easy enough for a competent person to tackle?  Thanks again!  

on the blazer i had the actuator was under the battery tray.  all you had to do is remove the battery, then the tray.  the actuator is held in place with three screws and has a cable hooked to it going into the differential.  not to hard takes longer to remove battery and the tray then to remove and replace actuator.  becareful not to puncture the rubber diaphragm of the actuator or there goes  $70 down the drain.  

hey, thanks a lot for the help, now I know what I'm looking for, and I can save my brother a costly trip to the mechanic.  Thanks again!  

http://www.4x4posi-lok.com/s_series.html

Found this on the internet... try the 4X4 Posi-Lok, it replaces the stock vacuum actuator and won't leave you stranded like the the crappy stock vacuum will. It cost a little more that the stock actuator, but you'll only have to buy one... I have one for my K1500 and it works great, it won't leave you stuck at the time when you need it.  My stock actuator crapped out on me in a snow storm.

My brothers 4wd gave out in the snow too a few days ago.  The posi lock looks pretty cool, more reliable i guess.  thanks, I'll look into it.  

My friend had a 92 blazer and belive it or not the vacum lines were run in a very bad place for being done by chevy, they were run so that the rubbed on the sharp edge of the firewall, down beside the transmission, I personaly would take your battery out and then take the vacum line of the actuator and start the truck put it in 4wd and see if ther is vacume comming in the line, or because of the fact that it takes two people, one to start it and check for vacum, and one to hold the battery you could put it in 4wd and then take it apart and remove the line from the actuator and blow air into it with you mouth, if you hear air then you know you have a vacum leak but if not its mor than likely your actuator, and I personaly would put in a 4x4 posi lock. good luck.  

if i were you i would do the same thing i did...

just rig it up so the vaccume system is disconnected all together

then make that cable pulled all the time.

it does nothing at all when your driving it feels just the same

but it works and thats the cheap trick of the day

if you do it right your 4x4 light will allways be on (in the center where your transfercase lever is)

black tape over that and you will allways have 4x4 and 2x4 when you want it... at no extra cost to you.

SKBLAZER is right you could just make your own manual cable actuator.  Check your local parts store, I found a heavy duty push/pull locking T handle cable at an O'Reilly auto parts store, other places might have them, also.

no no you read it wrong, i said keep it locked in manualy.

your idea would work but it would be much more effort in doing.

im going for cheap and free, and time is money as they say so just make it all time locked in.. but it will still have 2 and 4 wheel drive

that system is 100% eliminated when you do it my way thats 100% cheaper and 100% less prone to breaking.

trust me if you lock it in you will be fine when you put the transfercase into 2 wheeldrive it will be ... 2 wheel.

very simple

For those of us concerned with gas mileage and tire wear, permanently locking the front differential actuator into 4wd will adversely affect both of these. This is probably not an issue if this a dedicated wheeler, but more so if it is a daily driver.

Doing this will have the exact same effect as operating a vehicle equipped with manual hubs in the locked position at all time. Your front tires will be constantly rotating the entire front drive assembly, including the front driveshaft while in 2wd.

MileMarker has sold thousands of full-time to part time hub conversion kits for a reason.

I definately reccomend the posi-lok cable actuator, bullet proof.

No, I knew what you meant 100% on all the time.  I was offering a cheap solution to lock and unlock the front end.  Not everybody wants to drive around with the front end engaged all the time.  Plus, it gives you the option of 2-HI, 2-LO, 4HI, and 4LO.  

its not really locked into 4x4 and it would be like driving a streight axle around.

its a blazer for a 100 bucks (what that kit costs) i could get a full set of tires and rims. maybe a whole blazer.

but your right if its a truck your driving all day and dont really fourwheel with that kit is the way to go.

If you want to be fancy you can cut the vacuum line to the module.  Then put a tee into the vacuum line to the vacuum. off of the tee put a small ball valve.  then you can disconnect your front axle

things we do for ours s-10's