Engine/Transmission (1998.5 - 2002) No 4x4.. Help

[Tony0625]

So I did a clutch job my truck and I broke a vacuum line for 4x4. I got some vacuum hose and fixed the line. We got a huge snow storm today and the 4x4 dash light comes on and off as it should bht nothing happens.. Its 2 wheel drive regardless. Not super fromiliar with these systems so any info will help.. Thank you

 

[Tony0625]

Its a 2001 3500 nv5600 6 speed

 

[klcammie]

Does your heater door work like it should? Maybe one of the other vacuum lines came off. Does cruise control work? Did all linkages get hooked back up?

 

[Tony0625]

Heater door works.. But cruise has never worked. Pulling the trans there was one connector on right side of trans, two vacuum lines that go to the actuator, and one vacuum line connector for left side of trans. Nothing to miss. It worked great before the clutch job

 

[JR]

Once you shift the t case into 4wheel drive does the front driveshaft lock up. It should free wheel in 2 wheel drive but not 4 wheel. Also are you sure you put the vacuum lines back in the correct order.

 

[Tony0625]

yes the driveshaft does lock up when in 4x4 but i did try and switch them around and nothing changed

 

[JR]

Do you have vacuum at the actuator at the front axle?
One line should have vacuum while in 2 wheel drive and the other line should have vacuum when switched into 4wheel drive. It's been a long time since I had to mess with the POS set up and can't remember which line does which.
If you do have vacuum like I described above and the front end is not engaging, swap the lines at the front axle and move the truck forward and back a few feet (with the transfer case engaged in 4wheel drive). I hate the CAD set up on these trucks, they won't always engage the front axle when the truck is stationary. Sometimes you have to roll it forward or back to get the collar to engage the right side shaft. One of the best upgrades one can do to these trucks is a Posi-Lok system. It eliminates all the vacuum lines.

 

[Road Dog]

The 4WD light on the dash is driven by a switch on the CAD so if it turns on then the actuator is moving and sliding a collar to connect the axle shaft.

 

[Woodenhead]

It's possible that the shift fork on the CAD moves far enough to hit the switch and make the light come on but not engage the collar. Weak vacuum or a leaking diaphragm could cause this, be careful because if it's partially engaged it could do damage. I suspect you maybe still have a vacuum leak somewhere.
I've replaced mine on the last two trucks with one of these setups http://4x4posi-lok.com/app_dodge.html. It gets rid of the problem prone vacuum setup and lets you use low range in 2wd which is nice for backing up trailers, especially with an aggressive clutch.

 

[woodtrucker]

I'll second that posilok. Put one on a gasser ram I had b/c the shift fork wouldn't engage and I couldn't get into 4x4. Got the posilok installed and boy do I miss it on my 02 cummins I have now. Especially backing trailers with 2wd lo. I ride the clutch a lot b/c reverse is geared way too high on these trucks with 3.55's.
On my 02, I've had the opposite problem. The 4x4 light burned out but 4x4 still works. I think I'll leave that alone as long as I know the 4wd is working. so far so good...Only negative you get with posilok is that it's been my experience you MUST be rolling to engage it in 4wd. I never could do a neutral slight roll or slight reverse to get it to lock in. It worked best I was coasting in 1st gear.