I have two older Chevy 4 wheel drive vehicles, one 1991 S-10 Blazer and one 1996 S-10 truck. Both have no front wheel pull when in 4 wheel drive, the blazer I have yet to check for front drive shaft spin when it is pulled(manual pull on the floor) into 4WD but the pickup I had on a lift and i shifted (push 3 button on the dash near between the inst panel and climate control) into 4WD, the front drive shaft was spinning but the wheels were not spinning at all.

The blazer is very loose going down the road, I have had the truck for almost 15 years and its never been this loose, all front end parts bjoints, tie rods, control arms all check out good but the steering is very loose and sloopy

any ideas where to start on either of these problems?

 

The problem on both of these trucks is with the front axle engagement. Both are vacuum controlled from a switch on the transfer case. This switch takes manifold vacuum and directs it to a vacuum actuator either on the fender (as in the '91) or under the battery (as in the '96). This actuator pulls on a cable to engage the front axle. Check for vacuum at the actuator as well as for proper operation of the actuator (vacuum pump will help here).

 

I pulled the battery tray on the 96 and I can pull the actuator in and the cable appears to move about an inch and a half, but when I push the button for four wheel drive nothing happens. If I pull off the cable the actuator pulls itself all the way in regardless of whether its in 2hi of 4hi,4lo, would this mean there is something wrong on the front axle or is the switch on the front axle bad? Also, i noticed there is a black ball mounted on the hood over by the hinge on the drivers side with nothing going to it I think that is the resevior but am not sure how it would hook to any lines, as there are none loose over on that side of the engine compartment. I did follow the line to the drivers side of the intake manifold and I have vacuum to the line going to the actuator so im completely lost now, any ideas? I sure appreciate the help!

Jeff

 

The black Orb thing on the drivers side under the hood i think is a vacuum reservoir? their definitely should be a vaccum hose going from that down to a T which hoses off down onto your t-case and i think from what ive heard on here the other stuff goes to your HVAC controls and other things. noone reem my butt for being wrong, just giving a little insight, but definitely needs something going to it

 

Yeah that's a good question about the "black ball". That is very needed for some accessories I thought as it carries the reserve vacuum needed to operate them properly. You definitely should start looking into why it's not hooked up. They do create pinholes & cracks which is a obvious leak. May have been bypassed to get passed an idle problem, but that's improper.

 

If nothing is connected to that black ball your 4wd won't work, or the front won't engage. Atleast on my 97 blazer when the hose came off that accumulator (think that's what it's called) my 4wd didn't work. Like they said above right below that next to the driver side fender by the firewall is a T and there will either be a no hose going to part of it or a hose hanging. I think it's about a 8 inch long hose.