95 Jimmy 4WD Problems

Where do I start. Ok I have the 3 push button electronic switches.
I push the 4hi switch and it lights but no front wheel engagement. I push the 4lo switch it lights I hear the clunk but no front wheel engagement. If I drive a couple of blocks smoke starts poring from my exhaust. The smoke stops when I switch back to 2hi. I checked the vacuum actuator under the battery and the cable had come loose from the actuator. I lubed the cable and replaced the actuator ( it had a hole in the diaphram) I tried it again thinking I had fixed the problem. But after a block or so the smoke came pouring out again and when I tried to switch back to 2hi I could hear a noise coming from the front differential like it wasn't disengaging all the way. so I put it back into 4hi drove home disengaged the cable from the actuator and then could drive in 2hi without hearing any noise from the differential.

#1 What causes the smoke when driving in 4wd even without the 4wd engaging?
#2 Why doesn't the 4wd engage?
#3 Why the noise from the differential when going back to 2wd?
#4 There are no codes showing after doing the pin 13 ground trick.
#5 Do you think replacing the vacuum switch on the transfer case will help?
maybe thats why the actuator won't let the differential completely disengage when going back to 2wd?

Thanks,
Buddy Clark

Classic vaccuum switch problem. Your right the vaccuum switch on the transfer case is bad and is causing the vaccum to suck up transmission fluid through the vaccuum line and into the engine where it is burn it and causing that nice smoke show.

Now the bad part. you have to get all the oil out of those lines. Check the vacuum ball under the hood(on the hood) and make sure trans oil hasn't gotton in there. The fluid causes delay engagement, and softens the rubber in the system where it will usually tear causing more engagment problems.

Good Luck!

That explains the T-fluid smell coming from the vents while the heater is on and probably why im only getting air from the defrost vents. None of the others work.

I just found another problem. The front seal on the transfer case also needs replacing which had allowed even more fluid into the case.

Is there an easy way to drain the lines? Are they hard to get to? Can they be vacuumed out? blowed out?

Thanks,
Buddy~

I replaced the bad transfer case seal and the vacuum switch and the actuator and installed a new actuator to differential cable.

Now I am getting vacuum to the actuator in 2Hi and no vacuum in 4Hi!

I double checked the connection at the transfer case vacuum switch and I have it connected right.

Also If I drive in 2Hi there is a clicking sound coming from the front differential. (Because the vacuum is pulling the cable) If I put it in 4 Hi the clicking goes away but There still is no lock in. ( because there is no Vacuum)

I can hear the rear lock in when 4lo is activated so I'm pretty sure the transfer case motor is working.

Could the Transfer case control module (TCCM) be causing the vacuum problem? Anyone have any ideas?

Thanks,
Buddy~

Check for good engine vacuum to transfer case switch.
Then check for vacuum from transfer case switching to front Axel solenoid in 4W H or low.
And also for vacuum switch switching good vacuum to front axle diagram and pulling cable good.

Try this link.
http://www.automotiveforums.com/vbulletin/showthread.php?t=572914

I think the vacuum lines from the transfer swich may have been routed wrong during a recent engine replacement. Is there any diagram to show the proper routing in relation to the switch ?
O.O
O

Thanks,
Buddy~

A factory repair manual or.
http://www.alldata.com/products/diy/index.html
Some public libarys have car repair info.

Great! Thank You for all your help:biggrin: I found the answer at this link:http://www.automotiveforums.com/vbul...d.php?t=572914 (http://www.automotiveforums.com/vbulletin/showthread.php?t=572914)

Ill work on my 4WD problem again this weekend.

Thanks again,
Buddy~

I ended up having to take my Jimmy to the shop.
Turns out the gears in the front differential were shot and a nylon washer was missing(maybe ground up with the gears)

Any way $400.00 fixed it. Not counting what I spent on a new actuator, new cable, new transfer case vacuum switch, new seal between transfer case and transmission, new interrupter switch on the differential and all my time.

You are welcome and thanks for posting back how it went.
Some times a cheap easy fix and sometimes a expensive deal.
Glad you got it fixed.