1992 S-10 blazer front hub engaging sporadically
 

i have a manual shift for the 4x4, when im driving down the road the light telling you when the front wheels are engaged comes on and goes off all the time. also there is a loud grinding noise like the front hub is engaging and when i slow down to about 10 mph there is a loud clunk and the grinding goes away.they dont happen at the same time the light thing happens alot more. i capped the vacuum line coming from the transfer case before the light sensor and the light doesnt come on and the engaging hasnt happended yet but i just capped it yesterday.im thinking that there is a problem in the transfer case sending vacuum sporadically.can anyone help me.

Sounds like your front axle engagement cable is froze up with the front axle partially engaged. It is possible that it has already damaged the mating gears inside the passenger side extension housing. Check out the Tech Article (DIY) index link in my signature and look for 4wd Front Axle Clicking When in 2HI - Goes Away when in 4HI/4LO (or just click). There are pictures of what it looks like on the inside. This is pretty universal for all s-series 4wd front axles (not the same for the AWD axles though).

i can move the actuator bulb in and out freely and the cable moves also

seems as though it is with the vacuum since the light stopped coming on when i plugged it

Does the noise go away when you have it in 4wd?

Is there vacuum at the actuator when in 2HI? If so, then your vacuum switch on the transfer case is bad.

ill check if there is vacuum in a minute but some times it doesnt happen for an hour and sometimes twice in 5 minutes. also is the vacnnm switch on the transfer case internal or is that where the 3 lines hook to the side of the case

i just checked and it does have vacuum when in 2 wheel drive is that a hard fix?

Right where the three lines connect.

Could be a busted return spring inside the front axle.

i got the new vacuum actuator switch and installed it everything works great and a very easy fix, part was only 15 dollars. thanks alot for the help swartlkk