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-   -   My 4wd wont engage. (http://www.wranglerforum.com/f330/my-4wd-wont-engage-231593.html)

1994 jeep girl 03-31-2013 02:45 AM

My 4wd wont engage.
 
I have a 94 yj 4cyl 5 speed. I can put it in 4lo nd it gears way down like it should but my front tires wont pull. The drive shaft spins nd the hubs nd axles r fine. My cousin said i may need to "pen" the vacuum hose. Has ne one else had this problem?

Highvan 03-31-2013 03:20 AM

Does the light come on when you put it into four wheel drive? On my 87, there is a red hose that has to be "T" - ed into a vacuum hose. When i first got my jeep, mine worked fine, then i swapped in a bunch of new parts under the hood and i knocked that little hose off by accident and didn't realize it, then the next time i went to use my four wheel drive, the light wouldn't come on and the four wheel drive wouldn't work, so my guess is, that's what's wrong with yours, cause as soon as i reattached it, it worked fine again

1994 jeep girl 03-31-2013 11:02 AM

The light doesnt come. It has a few wiring problems so i thought it was just a part of that.

JD95YJ 03-31-2013 11:05 AM

the vacuum is notorious for going out on YJs.. Sometimes the diaphragm just gets stuck and you can remove it and get it unstuck by moving it a few times, using compressed air, etc.. You can replace the diaphragm, or add on a Posi-Lok system, or other ways to get around it as well. Good luck!

Gunz n tractorz 03-31-2013 07:52 PM

Check the vacuum lines. Put in 4wd and take lines off off diaphragm and see if there is suction on the lines. In not there is a problem with the lines, such as they have a hole in one of them or they just ripped in half like mine did.

cakes567 03-31-2013 08:55 PM

I would check the actuator first. Its very very common to get stuck. If that's not struck then check your lines and go from there.

kik 04-01-2013 11:42 AM

Quote:

Originally Posted by cakes567 (Post 3577387)
I would check the actuator first. Its very very common to get stuck. If that's not struck then check your lines and go from there.

X2. There's also a switch on the transfer case that could be bad.

Aswellguy 04-30-2013 10:25 PM

Any luck with your jeep? I have the same problem... Changed actuator and transfer case switch... Still no luck.

1994 jeep girl 05-01-2013 12:11 AM

Its the vacuum hoses. I found out they had melted in half some how.

dancin1 05-01-2013 07:46 AM

Get a diff lock, cable manually operated. $150.00 and never have that problem again, or fix the vacuum system for $150.00 and probably do it again, and maybe again. My diff-lock works great, would never go back.

n2trucking 05-01-2013 09:40 AM

Quote:

Originally Posted by dancin1 (Post 3705217)
Get a diff lock, cable manually operated. $150.00 and never have that problem again, or fix the vacuum system for $150.00 and probably do it again, and maybe again. My diff-lock works great, would never go back.


agreed but i did the washer trick in the half shaft lock. even cheaper. almost free. i had washers laying around but i bought a 4wd indicator switch from autozone for cheap that's for a chearoke and installed it into the t-case and ran the wire and that works great!

Aswellguy 05-05-2013 09:47 PM

Quote:

Originally Posted by n2trucking (Post 3705559)

agreed but i did the washer trick in the half shaft lock. even cheaper. almost free. i had washers laying around but i bought a 4wd indicator switch from autozone for cheap that's for a chearoke and installed it into the t-case and ran the wire and that works great!

How did you install the 4wd indicator switch?

n2trucking 05-06-2013 09:58 AM

Quote:

Originally Posted by Aswellguy (Post 3723374)
How did you install the 4wd indicator switch?


The jeep cherokes have the same kind of 4wd switch on the Transfer case but instead of it having vacum ends on it, it instead has an electric end and you can buy the matching pigtale that plugs into it. It will be a two wire pigtale and all you have to do is run the single wire from the firewall thats off the 4wd vacum light indicator switch and wire it directly to the new Transfer case switch and ground out the second wire thats on the Transfer case switch.

When you shift the T-case the new switch will finish the circuit and ground out the wires just like the 4wd vacum light indicator switch did just without using and vacum.:thumb:

So what my front axle is always locked. At least i know my 4wd works all the time and i don't feel any problems with the axle being locked.

n2trucking 05-06-2013 10:11 AM

2 Attachment(s)
Quote:

Originally Posted by Aswellguy (Post 3723374)
How did you install the 4wd indicator switch?


Here is what they look like.

Aswellguy 05-06-2013 12:44 PM

Quote:

Originally Posted by n2trucking (Post 3724641)

Here is what they look like.

Thank you! I will be doing this mod this week hopefully.

piercejoelm 05-06-2013 07:39 PM

Check your vacuum lines. Mine would not engage either on a 95 4.0. I checked all the wiring and traced the vacuum lines by the teams to the transfer case going into the switch, all were fairly new and in tact. I opened the hood and the vacuum hose that went to the most aft nipple on the intake popped off. I put it back on and threw a clamp on it. It immediately worked with the lights and all. Spending time looking for a bad vacuum line is a lot cheaper than doing a $150 mod that you probably do not need to do yet. Just my .02


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