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Discussion Starter #1
I'm a newbie, so bear with me. I got to sliding around in the snow today, threw it in 4hi...and got nothing. It was working fine a few months ago. Truck isn't abused, isn't leaking any fluids, and hasn't had anything out of the ordinary happen to it since it was working. What do I need to look at?
 

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Does the 4wd light come on? If it does, then it's probably your CAD (computer activated differential IIRC) unit on your front axle. Might want to consider looking up "Posi-Lok" if you find this to be the case.
 

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It's more than likely your CAD system. If you look on the back of the front axle on the passenger side you will see a vacuum motor with hoses running to and from it. First thing is to check for broken or disconnected lines, if everything looks OK, see if your lines are clogged.

Dodge CAD systems can be really tempremental and fail often. I have to manually engage my 4wd by pulling off one of the hoses after I shift since one of my lines are clogged.

EDIT: American ya beat me to it! Although I think you may have it backwards? If the light comes on, then the shift fork in the axle has moved enough to activate the light, and if that light is on and he has no 4wd he's got something in the axle broken. If the light DOESN'T come on, the CAD system hasn't engaged the shift fork due to poor airflow or a broken vacuum.
 

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:withstupid: about the light. If it doesn't come on, check to see that your vaccum lines going to and from it aren't damaged/loose/broken. You should be able to pull one line off and feel the vaccum. That's where I'd start.
 

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its you are in snow, it leads me to beleave it is below freezing, which means any condesation in the vacuum lines could have frozen up and lead to acracked line or plugged a line or held something in place that needs to move
 

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My light comes on, but 4Hi won't engage, but 4Low will. Dodge dealership said it was the CAD. Are they THAT retarded? And I am THAT retarded to trust a stealership? :silly:
 

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Well it could be that the shift fork isn't fully engaged, the light will come on before the shift fork gets all the way engaged.

Sounds like you got transfer case probs though? If you turn with the 4wd light on do the front tires lock up and jump? Driveshaft spinning?

Heck mabye the stealership is right? :bs:
 

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Discussion Starter #9
Hose "looked" alright. I didn't stay out there long enough to take it off, the wind chill is in the negative teens :shock: I'll give it a better look tomorrow. Thanks for some direction.
 

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On 2005-12-06 16:06, NJ Ram wrote:
Well it could be that the shift fork isn't fully engaged, the light will come on before the shift fork gets all the way engaged.

Sounds like you got transfer case probs though? If you turn with the 4wd light on do the front tires lock up and jump? Driveshaft spinning?

Heck mabye the stealership is right? :bs:
Driveshaft spins, but it doesn't buck and jump like in 4low. My driveshaft spins in 2wd sometimes though.
 

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On 2005-12-06 15:41, American wrote:
Does the 4wd light come on? If it does, then it's probably your CAD (computer activated differential IIRC) unit on your front axle. Might want to consider looking up "Posi-Lok" if you find this to be the case.

"CAD" stands for Central Axle Disconnect.

There is a vacuum actuated shift motor on the front axle that engages/dis-engages the right side stub shaft. If you remove the vacuum lines from the shift motor, when the transfer case is in 4hi & 4 Lo, you should have between 10-20 in hg vacuum to the line that connects to the outside port. With the TC in 2hi, the vacuum will be to the inboard port.
These are copies of the troubleshooting flow charts out of the 1988 Dakota FSM but the 2000 Ram FSM I have has the exact same flow charts so I'm not going to rescan it.

[img=500x696]http://www.walt-n-ingrid.com/images/photopost/data/542/1chart2.jpg[/img]
[img=500x681]http://www.walt-n-ingrid.com/images/photopost/data/542/1chart1.jpg[/img]
 

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Discussion Starter #13
Walt_Felix, I checked out your web site...great info and pics. I'm using a buddy's garage tomorrow so I can work out of the cold. I'm sure this will help trouble shooting.
 
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