Join Date: Apr 2011
aa21830 is offline
Re: 1992 S10 Blazer Transfer case
Not sure if the 1st gen system is the same as 2nd gen (although I suspect it's similar), but on 2nd gen trucks, common 4WD problems are:
1) Bad vacuum lines to the t-case vacuum switch, and/or the lines from the switch to the hub locker vacuum actuator.
2) Bad vacuum actuator. This is the actuator that pulls a cable that locks the front hub (under the battery try on 2nd gen's). It can go bad due to age, or because of a faulty t-case vacuum switch that is letting ATF into the vacuum lines and into the actuator.
3) Bad transfer case shift motor. No shifty = no 4WD.
4) Seized hub locker cable. Sometimes all of the above are fine, but the cable won't budge.
Even if the LED's don't light up, you should still hear that distintive "thump" when the t-case shift motor engages, and/or the hub lock cable engages (sometimes the LED's don't light up because they are burned out...I've replaced the 4H LED on my '96 Sonoma twice).
Hope that helps.
2004 Blazer ZR2