# 96' Ram 4X4 Problem



## Eggie329 (Nov 25, 2009)

I just now finished fixing the U-joints on my 96' 2500 and put the drive shaft back in. It went in rough the first time (It sat 2 years before I bought it) and then pushed a huge pile of snow up a big hill. I left the lot and it felt like it was slipping and not in four wheel. Right now it seems like it either is no longer engaging in four wheel. The transfer case goes into four wheel fine but dosen't seem like the axle is locking. I'm guessing it is that actuator switch on the transfer case. Has anyone had a similar issue or what are some things to look at?

Thanks for your help!


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## 2robinhood (Apr 28, 2010)

It is actually the fork on the front rear housing which engages the front axles.
That is where the issue is.
It is either not working or isn't fully engaging.
I believe it is vacuum run.
Go on here and you will find all you answers.

http://dodgeforum.com/forum/2nd-gen-ram-64/


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## jmbones (Jun 17, 2009)

Not sure what fork you are talking about, the front axles are engaged and turning all the time unless you install manual lockout hubs. There is no vacuum, it is all mechanical. Once you throw the lever, it goes into 4x4 in the transfer case and engages the front drive shaft. If you notice when it is not in 4x4, and spin the front tires, the front drive shaft will still turn. So if you're throwing the lever into 4x4 and its not going in, it should be a transfer case issue. Simple test, get on some snow or dirt, engage the 4x4 lever and see if the front tires spin.


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## Chiputz (Dec 28, 2010)

Check the slip yoke on the drive shaft. The splines are probably stripped out of the yoke. Pull the driveshaft off, don't just look at it and try twisting it. If it stripped, you will not be able to move it by hand but the truck will spin it easy when you try to push. I've had that happen before. Good Luck.


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## Eggie329 (Nov 25, 2009)

I was trying to get under there to troubleshoot, but its a tad too cold to be working with the truck half way in the shop. I gave in and dropped it at a trans shop to see whats going on.


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## jmbones (Jun 17, 2009)

As Chiputz mentioned, maybe it is possible when you put the driveshaft back in that something went wrong. The shop should figure that out in no time.


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## Eggie329 (Nov 25, 2009)

Yeah, they should have it figured out. I'm figuring a vacuum line or axle lock or something. Thanks for the help!


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## RamDude01 (Feb 27, 2007)

I had the same thing happen with my 98 2500 last spring. It was the actuator switch on the transfer case. I replaced the switch and it still wasn't engaging - the rubber plug (which you cannot find anywhere) that goes between the vacuum lines and plugs onto the switch on the transfer case was not making a good seal on the nipples so there was a vacuum leak. I took out the rubber plug and ran the lines directly onto the transfer case nipples and have not had any problems since... just have to make sure that the lines are on the right nipples. Just something to look at... good luck.


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## justme- (Dec 28, 2004)

The splines on the drive shaft are pretty solid- not likely striped out.
Odds are the vacuum actuator on the front axle (yes the wheels turn the axles but there is a CAD in the axle which has a vacuum motor that locks the axle parts together allowing the front axle to be driven) or the vacuum switch on the top of the T-case. The vac switch is essentially a steel ball bearing in a housing that blocks or opens vacuum ports when moved and is moved by the internal shift fork in the T-case. Problem is the ball sticks from time to time- remove the switch make sure the ball is not stuck (has some spring pressure behind it but you can easily move it) Freeing it up is easy and reinstall. 

The front axle actuator is costly but easy to replace. Odds are the bolts holding the CAD cover in place will break off- expect that and be prepared to deal with it. If you need a quick fix you can remove the CAd cover, and move the shift fork to hold the collar in the locked position (fork held in place by e-clips on the actuator shaft) and reassemble. No gear lube in there- the axle seal is on the diff side of that CAD housing.
I ran that way for a year until I got around to fixing it right.


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## Eggie329 (Nov 25, 2009)

So I spoke with the trans shop and they easily got it into four wheel. Only problem is it won't come out! They said the front drive shaft is ready to come flying out from under the truck. They told me go find a new drive shaft, but how in the heck does a drive shaft go bad?


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## KevinACrider (Apr 3, 2008)

Quite ironic has I had the same problem and fixed it myself today, in the snow.

The metal vaccuum lines that connect the transmission to the actuator on the front transfer case had become rusted out.

What you should do first is to start at the actuator, take both hoses off and start the truck. Put your finger over the ends of the hoses. In 2wd you should feel suction on the red hose. Shift it into 4wd and the suction should switch to the black hose. If there is no suction on either one or both of the lines, go back to the transmission and disconnect the lines from the metal vacuum lines and repeat the test. If there is still no suction here, I'm honestly not sure what the problem is, but I would be surprised if you didn't have suction.

If you have suction at the first disconnect point but the 4wd is still not engaging, then your actuator switch is probably shot. For me I was able to just snip the vacuum hoses right before they connect to the metal lines and run new vacuum lines from there straight on the nipples of the actuator switch, by passing the existing metal lines, the other plastic lines and rubber connection. As someone else said, just make sure they are correctly installed. The red line goes to the passenger side, the black line goes to the drivers side of the actuator switch.


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## Chiputz (Dec 28, 2010)

Eggie329;1214711 said:


> So I spoke with the trans shop and they easily got it into four wheel. Only problem is it won't come out! They said the front drive shaft is ready to come flying out from under the truck. They told me go find a new drive shaft, but how in the heck does a drive shaft go bad?


A driveshaft can get twisted, bent, etc.. pick your poison. You can bend the ears on the yokes if you're not careful changing the joints. You didn't change the axle joints did you? Before you pull the axles, lock the front end in 4 wheel to hold the spider gears in place. Go thru the checks on the fork in the previous posts concerning the lube in the fork cavity when you get your truck back. Hopefully the bad shaft didn't mess up your transfer case. Good Luck.


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