4X4 Actuator - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > 4X4 Actuator

Safety Thimble FairleadsEngo winches available at www.rockridge4wd.com! Free shippBLACK FRIDAY SPECIALS!! You asked, we deliver!

Reply
Unread 01-04-2010, 09:57 AM   #1
reredrider
Registered User
1988 YJ Wrangler 
 
Join Date: Jan 2010
Location: N.C
Posts: 8
4X4 Actuator

Well there I was, 25 degrees and in tub deep water when the 4wd would not go in. The actuator is only 20yrs old so I guess it is time for a new one. I chose to go back with stock equipment from "Quadratec", they have the best price. I am changing the fork too. Are there any hidden tricks or issues putting this thing in? I have seen a lot about a posi-lock but I will give this factory equipment another chance.
I am new to this site and this is my first post, thanks for tha help...

reredrider is offline   Reply With Quote Quick reply to this message
Unread 01-04-2010, 10:00 AM   #2
rustywrangler
Got my eye on you.....
 
rustywrangler's Avatar
 
Join Date: Apr 2005
Location: Syracuse, NY
Posts: 18,616
to the forum.

Personally, I would have trouble shooted a bit more first. The actuator may be fine. You could very easily have a vac leak or the switch is shot at the tcase.

Have you looked it over at all???

Not trying to tear ya down, just saying, did you check everything first???


As far as the parts install, it is a fairly simple process. 4bolts and most of it is out.
__________________

Congenital Heart Disease is a reality for me, BOTH of my children have it. Please read up and become aware for future generations

Lydia Ann-Acquired 08/05/05 Open Heart surgery 08/10/05
Jacob Patrick-Acquired 01/17/08 Open Heart surgery 02/15/08
rustywrangler is offline   Reply With Quote Quick reply to this message
Unread 01-04-2010, 10:08 AM   #3
reredrider
Registered User
1988 YJ Wrangler 
 
Join Date: Jan 2010
Location: N.C
Posts: 8
Well after I got back the Jeep has been sitting because it is freaking freezing here. It acted up two times before by taking its time engaging and one time it didnt. I have not use it since I changed the Carb out to a MC2150, so I am not sure where that vac line connected.
reredrider is offline   Reply With Quote Quick reply to this message
Unread 01-04-2010, 10:17 AM   #4
rustywrangler
Got my eye on you.....
 
rustywrangler's Avatar
 
Join Date: Apr 2005
Location: Syracuse, NY
Posts: 18,616
If you have poor vac, it could be the culprit. BUT, after 20 years it cant hurt to replace the parts. While in there, I would look for any signs of dragging etc, by the shift fork.
__________________

Congenital Heart Disease is a reality for me, BOTH of my children have it. Please read up and become aware for future generations

Lydia Ann-Acquired 08/05/05 Open Heart surgery 08/10/05
Jacob Patrick-Acquired 01/17/08 Open Heart surgery 02/15/08
rustywrangler is offline   Reply With Quote Quick reply to this message
Unread 01-04-2010, 10:23 AM   #5
reredrider
Registered User
1988 YJ Wrangler 
 
Join Date: Jan 2010
Location: N.C
Posts: 8
Thanks, I am going out to look at it, it has reached 30deg now. Where does the vac hook to that makes it lock. Where is the vac coming from to make it work? Headed out to see real quick...
reredrider is offline   Reply With Quote Quick reply to this message
Unread 01-04-2010, 11:15 AM   #6
reredrider
Registered User
1988 YJ Wrangler 
 
Join Date: Jan 2010
Location: N.C
Posts: 8
Ok, I have a red vac line coming from the top of the trans, on the switch that has all the other vac lines hooked to it, that is not connected. Where does that draw vacuum from? It is coming from the switch to the motor. I hooked the vac from the distributor to it and the 4wd light came on, so I know it needs something. The axle still would not engage at that time. I pulled the green vac line, "closest to the wheel" off of the actuator and it felt like there was a small amount of pull on it. I am thinking the switch works but the actuator is not. Does that red vac line draw from the carb? I comes out on the passenger side of the motor compartment too.
reredrider is offline   Reply With Quote Quick reply to this message
Unread 01-04-2010, 11:44 AM   #7
73Dart
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: Shelby, NC
Posts: 620
Quote:
Originally Posted by reredrider View Post
Ok, I have a red vac line coming from the top of the trans, on the switch that has all the other vac lines hooked to it, that is not connected. Where does that draw vacuum from? It is coming from the switch to the motor. I hooked the vac from the distributor to it and the 4wd light came on, so I know it needs something. The axle still would not engage at that time. I pulled the green vac line, "closest to the wheel" off of the actuator and it felt like there was a small amount of pull on it. I am thinking the switch works but the actuator is not. Does that red vac line draw from the carb? I comes out on the passenger side of the motor compartment too.
Mine is connected to the va resivor located under the battery tray. From there it is connected to the base of the carb.
__________________
89 YJ with a 5.2l V8, 5 Speed ax-15, RC aals giving me 1.5" of lift plus 1" lift shackles giving me a total of 2.5" of lift, 31x10.5x15 A/T tires, no carpet, rinolined tub, Family style roll bar.

My motor swap thread
73Dart is offline   Reply With Quote Quick reply to this message
Unread 01-04-2010, 11:49 AM   #8
reredrider
Registered User
1988 YJ Wrangler 
 
Join Date: Jan 2010
Location: N.C
Posts: 8
Aiight, guess I need to find a manifold port vac to hook it to, thanks..
reredrider is offline   Reply With Quote Quick reply to this message
Unread 01-15-2010, 09:04 AM   #9
falconwagon62
Registered User
1995 YJ Wrangler 
 
Join Date: Jan 2010
Location: Trenton, Ohio 45067
Posts: 2
What did you find? I have the same problem, light on and front NOT pulling, and the driveshaft spins free....Don't want to ask a question that has been asked 100 times...john
falconwagon62 is offline   Reply With Quote Quick reply to this message
Unread 01-16-2010, 08:19 PM   #10
73Dart
Registered User
1989 YJ Wrangler 
 
Join Date: Mar 2009
Location: Shelby, NC
Posts: 620
Quote:
Originally Posted by falconwagon62 View Post
What did you find? I have the same problem, light on and front NOT pulling, and the driveshaft spins free....Don't want to ask a question that has been asked 100 times...john
Is the front driveshaft spinning free when it is suppose to be in 4wd. If so there is a problem in the transfer case.
__________________
89 YJ with a 5.2l V8, 5 Speed ax-15, RC aals giving me 1.5" of lift plus 1" lift shackles giving me a total of 2.5" of lift, 31x10.5x15 A/T tires, no carpet, rinolined tub, Family style roll bar.

My motor swap thread
73Dart is offline   Reply With Quote Quick reply to this message
Unread 01-16-2010, 08:38 PM   #11
bernm8r
Registered User
1990 YJ Wrangler 
 
Join Date: May 2009
Location: Sullivan County NY, New York
Posts: 356
The light on the dash means nothing really. IF you connected the vacuum to the wrong line it will light your dash up. or if you switch it around it will light up when in 2wd and go off in 4wd. You need to follow some basic trouble shooting. get a diagram of how the 4wd vacuum system is SUPPOSED to be.
Here is some info in the FAQ section under
http://www.jeepforum.com/forum/f12/f...y-here-451154/

4WD Engagement problems:
This information applies only to stock Dana 30 front axle disconnect of the 87-95 YJ jeep models.

One of the most common questions asked by new jeep owners is, “Why isn’t my 4wd working?” Though there are several possible reasons why the 4wd system of the jeep may be malfunctioning, the most common answer lies in the vacuum disconnect system that these models use. To understand why, you first need to understand how this system works.

The heart of the system lies on the passenger side of the front axle, just behind the wheel. There is a small molded box on axle tube that houses the disconnect shift fork which is connected directly to the shift motor. The axle shaft on this side is split into two sections, an inner section that connects to the housing and the differential, and an outer shaft that runs from the housing to wheel hub. When 4wd is engaged via the transfer case selection lever, the shift fork in the housing slides a collar from the outer shaft onto the inner shaft, coupling the two together so that they spin as one piece. If this fork fails to move, the shafts are not joined.

The jeep uses and open differential on the front axle (as well as the rear), which means that power is sent to the wheel that has the least amount of resistance. Under normal circumstances, like dry and semi dry pavement, this isn’t a problem as both wheels usually have somewhat equal resistance and thus power is transmitted roughly equally. If stuck in the mud or snow however, it is possible for one wheel to have no resistance. Thus all of the power will be transmitted to that wheel, causing the one that has traction to remain still, while the one that doesn’t just spins and spins. You’re stuck. This characteristic of the differential also holds true if the two piece shaft isn’t coupled via the collar. Since the inner shaft has the least amount of resistance because it isn’t connected to anything, all of the power is applied to it, thus robbing the driver side of any movement.

To move the fork, Chrysler decided to use a vacuum powered motor. A vacuum source line is run from somewhere on the engine (the location varies and can come from the brake booster, the manifold, etc) to a vacuum switch on the transfer case. When 4wd is selected, the switch sends the vacuum along several lines to the shift motor located on the front axle. The vacuum pressure is applied to a diaphragm inside the motor, thus sucking it one way or the other, depending on whether the axle is engaging or disengaging. The diaphragm is connected to the end of the shaft that the shift fork is attached to, thus moving the fork along with it. The problem with this system generally lies in the vacuum lines themselves. Over time, the lines harden and crack and dry rot. The older the vehicle, the more likely this will happen. As cracks form, air leaks soon follow, lowering the amount of vacuum pressure that is in the lines. After a certain point, there is no longer enough pressure to move the diaphragm, thus causing leaving the fork motionless. More often then not this is problem with the system. Included below is a diagram of the 4wd vacuum system.






Other possible problems:
The shift motor itself has been known to fail in much the same manner as the vacuum lines. Cracks in the diaphragm as well as rust and corrosion of the casing all lead to air leaks. A new shift motor runs about $50-80 at www.quadratec.com depending on the year of the jeep.

Another common problem is the vacuum switch on the transfer case. Over time dirt can build up inside it, causing it to fail. This can be replaced for about $25.

How to know if it’s the vacuum system:
Usually the best indicator of this is the fact that the 4wd dash indicator light no longer works. The light is switched on and off by the same vacuum that moves the shift fork. If the light is not coming on and your front wheels aren’t turning under power, there is a good chance it’s the vacuum system.

The Posi-Lok (Posi-lock) System:
Often confused with a differential locker, the posi-lok kit is simply a manual system for moving the 4wd shift fork that replaces the vacuum system. A cable is attached to a handle inside the cab and routed through the firewall down to a modified housing that replaces the housing holding the shift motor on the axle. To engage 4wd, the user places the transfer case in 4 hi or low, and pulls the handle, moving the shift fork to couple the two piece axle shaft. This eliminates totally the need for any vacuum pressure to be present at either the case or the axle, making it a much more efficient system, less prone to failure.

Cost:
Though marketed at about $200 dollars, the posi-lok can often be found on sale for $180, and sometimes even $160. Ebay may yield even better results. Run searches in the Shopping sections of the more popular search engines and you’ll find many dealers and will be able to sort by lowest price first. Just be sure it is meant for Jeeps as there are many trucks/SUV’s out there that use a similar system and Posi-Lok offers different kits for most of them. At this time, Jeeps use the 9000 series. For the DIY people, there have been write-ups on making your own cable system using bicycle shifters and miscellaneous parts. One such write-up can be found here: http://home.earthlink.net/~stevenschreiber/cabledis.htm There may be others out there. Search for them on the net.


This is a copy of the install instructions I got for my carb

There are two types of vacuum pull that you will need to understand. They are “ported”
vacuum and “manifold” vacuum. It is EXTREMELY important to know what type of
vacuum source each port is pulling, and to know and understand which vacuum source is
needed for each device. Example: Your distributor advance needs ported vacuum. The
ported vacuum pull advances your distributor timing as you accelerate. If by chance you
tie into manifold vacuum by mistake (and properly adjust your timing) you will actually
retard your timing as you accelerate. This is BAD by the way and you will be very
sluggish off the line and at WOT.
Ported Vacuum
-Ported vacuum is drawn in when the throttle is opened up. This draw is increased as
more air is sucked into your air through cleaner and down through the venturis. Ported
vacuum is highest at W.O.T. and lowest (or non-existent) at idle. You will have almost
no vacuum pull at idle with ported vacuum unless you have moderately high idle speeds..
Manifold Vacuum
-Manifold vacuum is drawn when your throttle is closed or at idle to very low driving
speeds/RPM’s. This is everything under the carb. It is highest at idle and lowest at
W.O.T.
Checking Vacuum Type
The easiest way to check vacuum ports and telling what type of vacuum they are drawing
is to start the engine with the vacuum ports capped off and uncap them one at a time.
Once you uncap the port, touch the opening with your finger (at idle) if it sucks on your
finger tip it is probably manifold vacuum. Increase to full throttle, the suction should
dissipate. If the vacuum is ported, it should have little to no suction at idle and should
start to draw respectable suction as acceleration is increased. Ported vacuum will reach
peak suction at W.O.T
bernm8r is offline   Reply With Quote Quick reply to this message
Unread 04-01-2010, 03:01 PM   #12
royalhighness
Registered User
1989 YJ Wrangler 
 
Join Date: Jan 2010
Location: Denton, TX
Posts: 18
I'm pretty sure that, you sir, are a genius!!

Quote:
Originally Posted by bernm8r View Post
The light on the dash means nothing really. IF you connected the vacuum to the wrong line it will light your dash up. or if you switch it around it will light up when in 2wd and go off in 4wd. You need to follow some basic trouble shooting. get a diagram of how the 4wd vacuum system is SUPPOSED to be.
Here is some info in the FAQ section under
http://www.jeepforum.com/forum/f12/f...y-here-451154/

4WD Engagement problems:
This information applies only to stock Dana 30 front axle disconnect of the 87-95 YJ jeep models.

One of the most common questions asked by new jeep owners is, “Why isn’t my 4wd working?” Though there are several possible reasons why the 4wd system of the jeep may be malfunctioning, the most common answer lies in the vacuum disconnect system that these models use. To understand why, you first need to understand how this system works.

The heart of the system lies on the passenger side of the front axle, just behind the wheel. There is a small molded box on axle tube that houses the disconnect shift fork which is connected directly to the shift motor. The axle shaft on this side is split into two sections, an inner section that connects to the housing and the differential, and an outer shaft that runs from the housing to wheel hub. When 4wd is engaged via the transfer case selection lever, the shift fork in the housing slides a collar from the outer shaft onto the inner shaft, coupling the two together so that they spin as one piece. If this fork fails to move, the shafts are not joined.

The jeep uses and open differential on the front axle (as well as the rear), which means that power is sent to the wheel that has the least amount of resistance. Under normal circumstances, like dry and semi dry pavement, this isn’t a problem as both wheels usually have somewhat equal resistance and thus power is transmitted roughly equally. If stuck in the mud or snow however, it is possible for one wheel to have no resistance. Thus all of the power will be transmitted to that wheel, causing the one that has traction to remain still, while the one that doesn’t just spins and spins. You’re stuck. This characteristic of the differential also holds true if the two piece shaft isn’t coupled via the collar. Since the inner shaft has the least amount of resistance because it isn’t connected to anything, all of the power is applied to it, thus robbing the driver side of any movement.

To move the fork, Chrysler decided to use a vacuum powered motor. A vacuum source line is run from somewhere on the engine (the location varies and can come from the brake booster, the manifold, etc) to a vacuum switch on the transfer case. When 4wd is selected, the switch sends the vacuum along several lines to the shift motor located on the front axle. The vacuum pressure is applied to a diaphragm inside the motor, thus sucking it one way or the other, depending on whether the axle is engaging or disengaging. The diaphragm is connected to the end of the shaft that the shift fork is attached to, thus moving the fork along with it. The problem with this system generally lies in the vacuum lines themselves. Over time, the lines harden and crack and dry rot. The older the vehicle, the more likely this will happen. As cracks form, air leaks soon follow, lowering the amount of vacuum pressure that is in the lines. After a certain point, there is no longer enough pressure to move the diaphragm, thus causing leaving the fork motionless. More often then not this is problem with the system. Included below is a diagram of the 4wd vacuum system.






Other possible problems:
The shift motor itself has been known to fail in much the same manner as the vacuum lines. Cracks in the diaphragm as well as rust and corrosion of the casing all lead to air leaks. A new shift motor runs about $50-80 at www.quadratec.com depending on the year of the jeep.

Another common problem is the vacuum switch on the transfer case. Over time dirt can build up inside it, causing it to fail. This can be replaced for about $25.

How to know if it’s the vacuum system:
Usually the best indicator of this is the fact that the 4wd dash indicator light no longer works. The light is switched on and off by the same vacuum that moves the shift fork. If the light is not coming on and your front wheels aren’t turning under power, there is a good chance it’s the vacuum system.

The Posi-Lok (Posi-lock) System:
Often confused with a differential locker, the posi-lok kit is simply a manual system for moving the 4wd shift fork that replaces the vacuum system. A cable is attached to a handle inside the cab and routed through the firewall down to a modified housing that replaces the housing holding the shift motor on the axle. To engage 4wd, the user places the transfer case in 4 hi or low, and pulls the handle, moving the shift fork to couple the two piece axle shaft. This eliminates totally the need for any vacuum pressure to be present at either the case or the axle, making it a much more efficient system, less prone to failure.

Cost:
Though marketed at about $200 dollars, the posi-lok can often be found on sale for $180, and sometimes even $160. Ebay may yield even better results. Run searches in the Shopping sections of the more popular search engines and you’ll find many dealers and will be able to sort by lowest price first. Just be sure it is meant for Jeeps as there are many trucks/SUV’s out there that use a similar system and Posi-Lok offers different kits for most of them. At this time, Jeeps use the 9000 series. For the DIY people, there have been write-ups on making your own cable system using bicycle shifters and miscellaneous parts. One such write-up can be found here: http://home.earthlink.net/~stevenschreiber/cabledis.htm There may be others out there. Search for them on the net.


This is a copy of the install instructions I got for my carb

There are two types of vacuum pull that you will need to understand. They are “ported”
vacuum and “manifold” vacuum. It is EXTREMELY important to know what type of
vacuum source each port is pulling, and to know and understand which vacuum source is
needed for each device. Example: Your distributor advance needs ported vacuum. The
ported vacuum pull advances your distributor timing as you accelerate. If by chance you
tie into manifold vacuum by mistake (and properly adjust your timing) you will actually
retard your timing as you accelerate. This is BAD by the way and you will be very
sluggish off the line and at WOT.
Ported Vacuum
-Ported vacuum is drawn in when the throttle is opened up. This draw is increased as
more air is sucked into your air through cleaner and down through the venturis. Ported
vacuum is highest at W.O.T. and lowest (or non-existent) at idle. You will have almost
no vacuum pull at idle with ported vacuum unless you have moderately high idle speeds..
Manifold Vacuum
-Manifold vacuum is drawn when your throttle is closed or at idle to very low driving
speeds/RPM’s. This is everything under the carb. It is highest at idle and lowest at
W.O.T.
Checking Vacuum Type
The easiest way to check vacuum ports and telling what type of vacuum they are drawing
is to start the engine with the vacuum ports capped off and uncap them one at a time.
Once you uncap the port, touch the opening with your finger (at idle) if it sucks on your
finger tip it is probably manifold vacuum. Increase to full throttle, the suction should
dissipate. If the vacuum is ported, it should have little to no suction at idle and should
start to draw respectable suction as acceleration is increased. Ported vacuum will reach
peak suction at W.O.T
royalhighness is offline   Reply With Quote Quick reply to this message
Unread 04-01-2010, 03:47 PM   #13
srf4life
Registered User
1989 YJ Wrangler 
 
Join Date: Feb 2009
Location: Virginia Beach, VA
Posts: 66
Thanks so much for this as I just noticed that the 4WD indicator is no longer working in the dash. This was found out in the mountains, on the trails.

I will be checking the t'case switch and verifying my vacuum lines!!!!
__________________
1989 YJ, 4.2L, Weber 32/36, Nuttered, 33 inch BFG AT's on 15x10 Eagle Alloys, 2.5 inch Rough Country, 3/4 inch Warrior Shackles, Ground Pounder Fab Rear Bumper with Swing Out Tire Carrier
srf4life is offline   Reply With Quote Quick reply to this message
Unread 04-21-2014, 12:58 PM   #14
clayhayes
Registered User
1989 YJ Wrangler 
 
Join Date: Apr 2014
Location: Oak Grove, Kentucky
Posts: 1
1989 jeep wrangler sahara problem

So I think my 4x4 problem lies in the vacuums. The transfer case is doing its job, the front drive shaft is spinning, etc. the shift fork was broke in half so I put a new one in it. The 4x4 just won't lock in. The shift fork is not pushing over for some reason. I'm getting some kind of vacuum because my 4x4 light stays on until I mash on the gas a little bit, then it cuts off and comes right back on when I let off a little bit. Please help.
clayhayes is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.