Does ESOF stand for Eating S^&t Once Fourwheelin?

relays & fuses=good, little motor on transaxle=early retirement?, am I missing something? Should I remove motor and try to shift it with pliers, test motor and order a new one? I tried the "Chevy starter repair" (hit it with a hammer).

LL

 

When you engage the switch do you hear anything clunk?! Get out and see if you can turn the front drive shaft with your hand when engaged. Turn your A/C on full blast and then switch to 4x4...does it go to the defrost when you switch in to 4x4? Does your 4x4 light come on?

I wouldnt remove anything right now. There are a few things like I mentioned up above for you to do to give us a better understanding on whats going on. The ESOF is difficult to troubleshoot, but IMO not hard to fix once you narrow it down.

 

It does nothing, no clunk. I will start checking for voltage at the motor when the truck comes back from paint.

LL

 

Glad I don't have ESOF. I know I have to get out, but it works every time. Sorry that was of little help to you.

Now you've not helped us much either. What is it doing/not doing? I'm sure it is not engaging. What have you checked? To be truthful, there is but a handful of things that can be wrong with that system. Did I mention I hate ESOF?

 

Are you referring to the vacuum pump?

 

You're wheeling your rig and relying on a 4WD system that depends on vacuum to engage and disengage. That's a really bad combination. Ditch the ESOF and install a high quality manual hub like Warn Premiums if you plan on wheeling your rig.

 

The only part that is a "bad combination" is the vacuum pulse idea for locking the hubs. The transfer case is all electronic like other shift-on-the-fly system. Yes, using vacuum is not the best idea, but that's why you can still manually lock hubs. Problem solved, now you are just like the "regular" guys.

If you hear no clunks and your 4x4 light does not come on, then you have an electronic issue. I think there is a module for the ESOF under the dash. It could also be a connection that has become corroded or otherwise dirty.

Have you gotten out and checked your front axle shafts? Even though the 4x4 light doesn't come on, the hubs should lock (the transfer case engagement and the hub locking are 2 separate systems that work off of the same switch). Shift into 4wd, drive a few feet then get out, reach behind the tires and try to spin the front axles. If they don't spin, then they are locked and 1/2 of your system is working.

If your ventilation goes to defrost when you shift into or out of 4wd, then you have a vacuum leak (in addition to your electrical one).

If you turn your switch to 4wd, your transfer case doesn't engage, your 4x4 light doesn't come on and your hubs don't lock, I'd start looking at the switch on your dash being broken or having a broken connection to it.

Just my .02

DISCLAIMER: I am not a mechanic, I've just spent lots of time working of my ESOF system.

 

Hubs don't engage, transfer case doesn't shift, nothing happens. No weird vacuum related issues (A/C, etc) I've tried every test (thanks guys). When I get her back Friday with a new paintjob, rear bumper and a retractable metal bedcover (900 for all, SCORE) Ill check the connections and switch. I think the GEM is OK as everything else it controls works fine. I think I either have a bad switch (first check) bad connection or a bad transfer case motor. best way to test the switch? I thought just use my multimeter across ground and switch to see if its got 12v throughput, if I'm wrong let me know, I don't want to smoke the GEM.

LL

 

Oh, no clicking noises either, I checked the relays off the truck, they work, maybe I should listen to them on the truck, see if they're getting power. Also the 4 wheel low lights up when start as it should, there is NO indicator light on the switch even with headlights on, the more I thinks about it I may have a dead switch or I'm missing a blown interior fuse. I think procedure is pull radio and snap dash plate out but its been 20 years since I worked as a stereo installer.

1-is that the correct way to get to the switch?
2-is that the correct way to test it?
3-am I missing an interior fuse, the 30 amp under the hood is good.

LL

 

I half gave up on my ESOF. I lubed the autolock hubs, but still when I want 4x4, I get out, lock the hubs manually, and reach behind the wheels and turn the axle at the u joint until it clicks in.

 

I think you are on the right track