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4wd Not Working?

Winesalot
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Winesalot

Winesalot

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Yesterday I was trying to pull my loaded trailer out of a snow covered driveway.  I spun the tires in 2wd so I moved the transfer case shift lever from 2H to 4H but the front wheels did not spin on the snow while the rears were spinning.  I shifted to 4L and same thing.  I have no knowledge on these truck as far as the 4wd system.  Any thoughts or hints on what might have happened and how I should proceed from here?

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Winesalot

Winesalot

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3 hours ago, Rotax3006 said:

I have had mine not engage while I was stuck. Had to go forward and back to get the splines lined up.  Also had a line fall off right under the cab that feeds the actuator.  

 

That seems like what may be going on for me. I have used 4wd several times in the last few months and it sure felt like I was getting what I needed at the time. In this case my front wheels were not able to move at all once the rears started slipping. I assumed that when the 4wd indicator came on on the dash that it was engaged but I guess that is not the case. Hopefully I will have time tomorrow to do some investigation on the front end. 

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IBMobile

IBMobile

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1964317971_th3.jpg.73fccda5c269345da85f928cb5ed83a7.jpg

 

Check all your hoses and fittings for leaks and damage.  If your heater/vent ducks operate then you know the vacuum pump, hoses and fittings are good to the firewall. 

Old fittings like this will leak.  They can be replaced with a length of vacuum hose slid over the plastic line.

IMG_3758.JPG.990a309ef6000116857ecd0431c9bf98.JPG

 

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Tractorman

Tractorman

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On ‎12‎/‎30‎/‎2018 at 3:39 PM, Winesalot said:

I assumed that when the 4wd indicator came on on the dash that it was engaged but I guess that is not the case.

 

Reading through this thread, I do not see any information describing your truck,  so a lot has to be assumed. 

 

On my truck, the CAD unit (center axle disconnect) has to be actuated to turn on the 4x4 lamp.  The switch for the 4x4 indicator lamp is located on the end of the external vacuum operated portion of the CAD unit.  

 

If the 4x4 indicator lamp operates properly (off and on when it should be), then a vacuum leak is not likely your problem because the rod that the vacuum motor operates is what contacts the 4x4 lamp switch.  So, if the lamp lights when four wheel drive has been selected, then the vacuum motor has doen its job.  Likely there is a damaged shift fork or collar inside the CAD unit on the front axle.

 

- John

Edited by Tractorman
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2000Ram2500

2000Ram2500

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19 hours ago, Tractorman said:

 

Reading through this thread, I do not see any information describing your truck,  so a lot has to be assumed. 

 

On my truck, the CAD unit (center axle disconnect) has to be actuated to turn on the 4x4 lamp.  The switch for the 4x4 indicator lamp is located on the end of the external vacuum operated portion of the CAD unit.  

 

If the 4x4 indicator lamp operates properly (off and on when it should be), then a vacuum leak is not likely your problem because the rod that the vacuum motor operates is what contacts the 4x4 lamp switch.  So, if the lamp lights when four wheel drive has been selected, then the vacuum motor has doen its job.  Likely there is a damaged shift fork or collar inside the CAD unit on the front axle.

 

- John

 

I figured this out the hard way. I used my 4x4 once to make sure it worked and although i didnt need it and i was just out in the dirt it did work. Then a few months later i actually needed it and it wouldnt work. I just assumed it was the switch at the transfer case and it wasnt the issue. The aftermarket world sells the vacuum actuator kit to replace just the diaphragm and thats the route i went for cost saving. In my case the light wasnt coming on at all and once i replace the actuator it would come on again

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