I have a 02 3500 and it will not engage in 4wd. The level moves smoothly into both 4wd high and low. There is no indicator light on the dash and the front axel is not engaging. Where do I start. Please Help!!

 

Welcome to DTR

Check the most obvious and easiest first.
First check on drivers door for Mgf Date. If early 02, you have the CAD... disconnecting front axle.
To verify.... have someone look in wheel well while you creap ahead, in 2wd, to check if front driveshaft is rotating. Should not be.

If you have the CAD check on front axle.... center left, i believe, for the line that plugs into the axle.
It is designed to use vacume pressure to slide the shift fork and collar that engage the front axle.
This line can get bumped off and/or will disconnect if you have changed shocks/springs, etc and let the front axle hang free while on jack stands.
Actually think all 02's have the vacume line.... with or w/o the CAD, but not positive.

RJ

 

Thanks for the response RJ. I did notice that there was something bolted on the passenger side of the front Axel. It has 2 vacuum lines and wires running to it. Is this the CAD? Also, what throws the 4wd light on?

 

That must be it (don't have my truck here) .... nothing else on the axle I can think of.
But you may have the front differential vent tube added later to 02's. It runs up outside the frame and into the engine bay.

The dash light is activated by an indicator switch that plugs into the axle shaft engagement motor. The shift motor gets a vacuum signal from a switch mounted on the trasfer case.

If you have 4x4 but no light (not what you say is the problem) you need to replace that first switch and pray it's not the dash light itself.

RJ

 

I seriously doubt it's the dash light as they are LEDs, IIRC. First check to see that you have vacuum (cruise control and air cond. work properly). Then engage 4WD HI and drive around in a circle and see if you can bind the front axle (showing you are or aren't in 4WD). Check the vacuum lines up to the middle of the firewall where they connect to the main vacuum source. If 4WD can't be engaged (lights work when you put the key in to start, but not when you shift) then your CAD is probably bad. Not too hard to replace and cost about $80. Do a search here for more info.

Check here: RockAuto.com They have them under driveline, 4WD Actuator, for $76....

 

I will check for vacuum tonight and make sure the lines are not damaged. I definitely know my cruise control works and the front Axel is not engaging, so that leads me to believe the CAD is shot. Thanks again.

 

Pretty easy change once you get the kit from RockAuto.com .... What you want to do, though, is check the 4WD light and actuator before ordering the kit. Just take off the axle/CAD cover and move the shift lever to the left and have someone look in the cab for the 4WD light to come on....

 

Disconnected the CAD and pushed the the shift for over and no light came on. Also all vacuum lines were connected. Should there be power down to that switch? I checked both terminals from the wire with the key on and the transfer case in 4wd....no Power. Let me know what I should do.

 

I'd even go so far as to running the engine and trying to shift the fork over. Check the vacuum down there while you're at it. The left tube should be sucking in 4WD and the right should be sucking in 2WD. You can also push the collar by hand and see if the light comes on. If it's the actuator switch I think you can get that from RockAuto.com too. Short both wires and the light should come on. Run the wires and see if there's a short. My problem was the vacuum actuator on the transfer case which is impossible to change unless you drop the case.

 

did you get the 4wd working?

 

Still no 4wd. My concern is I can not get the 4wd light to come on. I will try and short out that switch tonight and see what happens. If I get the 4wd light to come on I am going to convert the vacuum line into a mechanical shift. What do u think about this product. http://www.puredieselpower.com/catal...t-p-25235.html

 

Dash lights have failed before. Rare but I have read it here.
No light when you first turn key on?

Main thing is getting 4x4 working.
Did you check Vacuum line all the way between transfer case and axle. I've had a line disconnect where they change over from hard lines to soft. It's on the inside of the right frame rail... just before they go to axle. One red (disconnecting locking collar, I think), one black.
Just a thought.

In my opinion, the vacuum line system works well. Once fixed... should last a long time.
I've been on DTR since 03 and read of very few problems on the 02's.... or earlier, for that matter. Your choice.

RJ

 

Thats what I did when I had the same problem. I bet its the vacume actuator tho the diaphram is probably out look at rock auto I wish I did. The only good thing about the posi lok is that you can ingauge 4 low and be in 2wd for sharper corners without the front binding. first have someone watch your front d-line with 4wd ingauged to see if it is moving, if it is moving than remove the vac actuator from the passingers side of the dif, attatch a vac hand pump to it and see if it moves it. let me know what you find out.

 

thanks for the advice. I will try those things tonight. I did notice that the 4wd light does not come on when the key is on. also all vacuum lines are connected the whole way back to the transfer case.

 

Quick update. I shorted out the wires going to the 4wd switch and the light came on. So I ordered the conversion to eliminate the vacuum. It should be here next Tuesday and installed that night. Thank u guys so much for your help.