Chevrolet Repair: 4x4 is not engaging, vacum, shift cable

Question
check fluid -it is good..When I shifted into 4x4 it didn't engaged..only 2x2 worked..it is a 1987 S-10 blazer..was told that all it needed was fluid...can you help me and tell what to look for..manual is not a big help..it is not a locking hub but shifter

Answer
Hi Thomas... check the vacum at the vacum pot it will be under the battery i believe in that year. it's the pot that has the front shift cable in it.if no vacum check the lines and the vacum solonid in the line to the pot. All the shifter does is shift the transfer case into gear vacum shifts the front axel into gear...hope this helps