4WD hang up?

[Rockhead]

Only when I need it! It snowed two feet here in NY yesterday. I backed out of my garage and punched the 4WD button. The light lit and I heard the tranfer case click in. Alas, the front hubs did not lock. I spun and spun and tried to get rolling so they might. I couldn't move more than a few feet at a time. I rocked and rolled and even tried 4LO. Again, the tranfer case did it's thing, but the fronts were asleep. Finally, and I mean after about 10 minutes, the front hubs got with the program and I drove away without any further hitches. Anyone experience this?

[Conman]

Only when I need it! It snowed two feet here in NY yesterday. I backed out of my garage and punched the 4WD button. The light lit and I heard the tranfer case click in. Alas, the front hubs did not lock. I spun and spun and tried to get rolling so they might. I couldn't move more than a few feet at a time. I rocked and rolled and even tried 4LO. Again, the tranfer case did it's thing, but the fronts were asleep. Finally, and I mean after about 10 minutes, the front hubs got with the program and I drove away without any further hitches. Anyone experience this?

It's a vacuum pump so it's sleepy when cold/wet. Some people convert theirs to manual pull cord. I had the same problem yesterday, but it only took 10seconds to work. I left it in 4wd overnight just in case. No problems today shifting in and out. Appears all GM trucks suffer this "trait".



Cheers,

Con

[Conman]

Here is the link:

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





About 130bucks give or take. I think JCW sells it.



Cheers,

Con

[quickbiker]

Yea, those posi locks are good. I've been debating the issue, cause there is some nice advantages, but my stock setup is working great for now.



I do remember a tb from GM on the issue for 01's, dunno about other years.

[seapahn]

The vacuum actuator is located under the battery tray. It is not uncommon for these things to stick. They basically pull a wire when vacuum is applied. I would also guess that's most likely why the fronts were not engaging.



FYI, on the S10s, the hubs are always engaged with the half-shalfts. The engage/disengage is done in the front differential using this cable.



You can try to pull that cable by hand by compressing the vacuum actuator, although it's a bit hard to get to with the battery in place. Definitely don't try it if the engine is hot cause you may burn your hand (You have to snake your hand down right next to the radiator). Getting to it from the bottom is NOT easy (best way is to take out the battery and the tray).

[seapahn]

Oh just to clarify ...



What I was trying to explain is if you are in a jam and need 4x4 to get out and this actuator thing decides not to work ... You can take this cable off and use a pair of wise-grips or something else to hold it pulled (to engage the front) ... so you can get to somewhere that you can get it fixed.



The posi-cable is also a good mod to do and a couple of people at zr2.com have that. The good thing about that setup is that it will give you 2LO !!! (just shift to 4LO but leave the front disengaged).

[HenryJ]

Another thing along these lines- My friend with the Highrider had an emabarassing moment.



He accidentally backed off an embankment and got stuck. the front tires were on dry pavement and the back wheels spinning. He couldn't move at all! The front axle would not engage since he could not move it at all.



He had to call for help. It didn't take much of a pull before it engaged, but he'll never live it down that his 4x4 was stuck with the front tires on dry ground