[hillie4life]

I engaged my 4 wheel drive to get out of the woods on friday and havent been able to get it out of 4 HI since.

I dont think that it is fully engaged because i tried going fast on some gravel and only the rears spun, the little light that says "4WD" is still on though and most problematic is the fact that as soon as I hit 45mph + on the highway I have a wicked vibration that only gets worse with speed.

So I'm thinking that it isnt fully disenaged.

I looked at the vaccuum lines and they are all attached.

I pulled the vaccuum lines off the actuator for a minute and the light went away, but i dont think that means anything, just that it cant sense it anymore.

I really need this resolved this is my transportation. Thanks

1989 Jeep 6cyl 258 2in body lift, 4 inch suspension lift. Never had an issue before with the 4WD always worked like a dream

[bhartwell59]

i was once told if that ever happened to drive slowly in reverse and do a figure-eight

[rockstedy]

also with driving backwards, put it in and out of 4x4 a few times just move lever back and forth a few times sometimes does it

[dbikers]

i had the same problem and it was this.....
the vacuum switch on top of the t-case (that has the 4 vac lines) had a broken tube on it.

The tube (i think it was for the green line) was for the vacuum to move the vac motor (on your front disconnect) back to 2wd(this same result would occur if my vac line to the disconnect was broken, cracked, melted, etc...). Thus, my axle disconnect was still engaged. This caused the light to stay on in my dash and caused my drive shaft to spin when in 2wd.


Also, the YJ DS is not balanced all that well (if at all) and mine is extra mangled so that caused the vibration. I fixed it by sending $16 to QUADRATEC for a new vac switch (i still never got another front DS but now it only spins in 4WD ...no vibration when on the street)


I would tell you to look at the vac motor on the disconnect and see if you are drawing any vacuum when you put it in 2wd...if not find out why and you will probably be able to fix it.
Good luck.

[hillie4life]

I took my lunch break and attempted to drive around the parking lot backwards for about 10 mins and nothing really happened.

As for the vacuum lines coming out of the Transfer Case, I had looked at them already, and from what I can see they looked like they were in good shape. But who knows just by looking right.

I will definately try testing the vacuum to 2HI I hadnt thought of that.

AS for now any more suggestions would be greatly appreciated as this my only form of transportation and I have to go 40 mph on the highway right now to keep my jeep in one piece.

Again, Its a 1989 4.2L 6cyl 258 M with a weber carb, 2 inch body, 4 inch suspension lift.

[dbikers]

Originally Posted by hillie4life

As for the vacuum lines coming out of the Transfer Case, I had looked at them already, and from what I can see they looked like they were in good shape. But who knows just by looking right.

Did you follow all of the lines from end to end? That may be a bit tough. in my case it wasn't a bad vac line, it was the 2wd port on the switch on the t-case. Pull the vac plug off of the switch on the t-case (the one in the pic with the 4 lines on it) and make sure that you have all 4 ports sticking out....mine was broken for no reason..

Also, did you just install the body and susp lifts? Possibly that you have pulled the plug off on an angle with the BL causing to either break the 2wd port or pull it off...

I think you should be able to make the front DS stop spinning (if you can't easily find the problem) as a temp band-aid to get home in 2wd ....i think you should be able to disconnect the vac lines on the vac motor on the front axle disconnect and take a tube or a straw and put vac on the 2wd side (again, i think it's the green one) to slide the disconnect back to the 2wd side and
then leave the vac lines off...that should disengage your axle and DS....let us know what you find
Anyone else?

[hillie4life]

So the popular thought is that it is a vacuum issue.

It wouldnt be a mechanical problem? maybe something to do with the transfer case/actuator/dif. being stuck?

Just putting my thoughts out there...

And how difficult would it be to replace some of those vacuum lines or plugs, and are the readily availible or special order?

[SniperYJ]

I had the same issue about a week ago. I just had a SYE and CV Driveshaft put in and when I took it for a test drive, it would not come out of 4wd. I tried a couple of things and nothing worked. Went to Advance Auto and got a transfer case switch and that was it. About $10-15 bucks and 10 minutes of work. Hope this helps.

[dbikers]

Originally Posted by hillie4life

So the popular thought is that it is a vacuum issue.

It wouldnt be a mechanical problem? maybe something to do with the transfer case/actuator/dif. being stuck?

Just putting my thoughts out there...

And how difficult would it be to replace some of those vacuum lines or plugs, and are the readily availible or special order?

is your jeep difficult to steer in the parking lot at low speeds or do you just have a vib at 45mph?

because it's old...you really need to find out if the vac is working to disconnect the front axle (if the disconnect is still in 4wd). Put it in 2wd and the trans in N...block the wheels so that it won't roll either direction, turn the jeep on, remove the vac hoses from the vac motor and see if the green hose has vacuum. If it does then you know it's not vacuum. It may be the motor but you won't know that until you pull it off.
the stuff that i listed in this post is what my problems were...you may not have the same problem

This is the vac switch i replaced (i have a 231, not sure what yours is)...it is $24.99 at quadratec http://www.quadratec.com/products/52247_00.htm but i think i got mine at autozone cheaper.
it was easy...thread the old one out and the new one in.


You could get a whole new set of vac hoses but until you know what the problem is i wouldn't spend any $$.

Here's a good link to "how things work" for the vac disconnect...it will give you a better understanding of how it works.
http://www.jeepforum.com/forum/showthread.php?t=573669&highlight=vacuum+disconnec t

i hope this helps

[hillie4life]

So last night after tracing all the vacuum lines around and checking everything I could see I got ahold of auto zone and sure enough they had the part!

I went there around 8pm and got their only transfer case switch, i even brought the one out of mine to make sure it was identical. ($13.99 btw)

Got it home, climbed underneath, figure tightened it in (smooth as butter), put the ratchet on it and began to tighten.... about 3 half turns later twisted the housing right off the end of the threads....

I nearly turned the jeep on and backed over myself! I couldnt believe how easily it broke off i didnt even have any resistance, it just twisted right off. After pacing around for a few minutes i retrieved the threading and o-ring from the top of the TC and began plan B.

I called a dealer and today during lunch im gonna get the OEM from them, $22 and hopefully this one will make it onto the Rig.

BTW the little ball type spring loaded piece was pushed all the way in on the old on and wouldnt come out... so im thinking that it could have been the problem... all of the ports looked intact.

Cross your fingers round two is this afternoon.

[hillie4life]

SO YOU GUYS ARE AWESOME.

Thank you so much for all of your help. It was exactly that, the "transfer case switch" was malfuctioning and causing a cut off in the vacuum system.

As soon as I replaced it and turned her on the light was gone, and just to test fate i slid it back into 4wd and then back into 2wd... and the light came back on a shut off with the lever... flawless.

Thank you again, so much! Especially Dbiker... the advice and pictures were priceless.

Thank you all.... I'm gonna go for a drive!

[dbikers]

thank you for letting us know of your success.
Glad it all worked out...you didn't take it to a hack....YOU fixed it....(feels good don't it!!)
happy wheelin'

[seanconrad]

i had the same problem with my 94 yj. i took the switch out and looked at the ball that compresses and it would compress but wouldn't let back out quickly, so i replaced that and works great. you guys are awesome

[mitch_brown]

i think your front axle is still engaged causing your griveshaft to spin and vibrate at higher speeds. 4x4 posi loc can fix you up for 180 dollars. It's easy to install and works very well.

[mitch_brown]

oh my bad i didnt know you already fixed it