No indicator light, Im thinking its the center axle disconnect. How can I check it? Can it be replaced with out pulling the axle? thanks, doug 96 2500

 

I dont know about fixing the problem, but to check your CAD, i would jack the front end of the truck up (both front tires off the ground) Have the truck in 4 wheel drive, spin one tire, if you have an open differential then the other tire will spin opposite direction if the CAD is working correctly. If you have installed a LDS or a Locker, the tires will spin in the same direction, once again, if the CAD is working correctly. If the CAD is not working at all, then the tire you spin will be the only tire that you spin. Make sure during this entire process that your front dive shaft does not spin, it will rotate a little but then stop, because the rear tires are on the ground. If your front driveshaft does spin, and your truck in is 4x4, then it may be your transfer case, and not your CAD.

or you could just put your truck in 4x4 and turn on dry pavement, you know if its working then, the inside rear tire will spin faster than the vehicle is moving and make your truck jump a little.

 

Posi Lock it

and forget it... Here is my write up on the posi lock kit . If you indicator light is not coming on, no vaccum is being created to push the axle disconnect awar towards driver side axle to actually stop grounding circuit,and give u 4wd light indication (terribly sorry for typos, broken right hand ) So, anyways.. If u dont want posilock, check all vaccum hoses, start with the ones up top at the fuel filter, follow those down to the t case,

another problem can be that the little connectors are covered in oil, clean them, possible leaks in the hoses,

Finally, u might have oil in the Actuator itself whic caused it to fail. 95 buck replacement part i think..

Regardless.. Posi lock it and forget it...

https://www.dieseltruckresource.com/...ight=Posi+Lock

https://www.dieseltruckresource.com/...cat=500&page=2



Tx

 

Most common cause is a broken or disconnected vacuum hose at the actuator on the axle, most often it will cost you nothing to fix.

 

Is it the 4X4 not working or just the light? To check the light disconnect the connector at the CAD unit on the front axle and put a jumper between the two wires. With the key ON the light shoulld come on. If not check the wiring and the switch in the CAD. The wiring on mine had broken up near the rad and the light would not come on ever even though the 4X4 worked fine.

I like to start with the easy stuff!

 

The Four wheel drive is not working or the light

 

Can I check it buy putting the transfer case in four wheel drive , and then check for vacume at the actuator?

 

Yes.
There are two hoses at the actuator, which one that has vacuum will depend on if you are in 2 or 4wd. There should always be vacuum at one of them.
If you have weak vacuum the most common cause is an acid rotted vacuum hose under the driver's side battery.

 

Yes there is vacuum on one, then the other. I guess I will buy a new actuator. thanks doug

 

Is that a dealer item only , I cant seem to find one online?

 

Dealer only. I would take it apart first and find what is exactly wrong first. Most of the parts are available separately.

 

For a quick check of the disconnect without having to jack it up, put the truck in 4x4 and drive a short distance to make sure it has a chance to lock in. Then shut the engine off with it still in 4x4. Once the engine is off, put the lever back into 4x2. Get out and try to turn the front driveshaft. If the disconnect is locked, the driveshaft shouldn't spin. If it spins freely, the disconnect isn't working.

This is also similar to checking the transfer case. If you think the t-case isn't locking in, shut the truck off in 4x2, then shift into 4x4. If the driveshaft spins, the t-case isn't locking in properly.

Once you know for sure the disconnect isn't working (I know you already checked), as others have said, you can check the vacuum to make sure you don't have a leak or have a bad switch at the t-case.

Once you know for sure the disconnect is at fault, before spending the aprox. $175 on a new one, or $200 on a posilock (money well spent), you can buy a $15-$20 vacuum pump and hook it up to the vacuum ports on the vacuum motor to see if it will move. Remove the disconnect to test it so you can see if the fork is moving or not. Sometimes the problem is a worn coupler, and not the vacuum motor itself...although that is very rare.

Jim

 

There are just a couple of things that will cause no 4x4: bad transer case, bad CAD, no vacuum, bad vacuum switch. Now there are quite a few things that can cause any of these problems - like oil in the vacuum lines, holes in the vac motor, broken switch, etc... First make sure the transfer case locks - put it in 4x4 & move the truck a few feet. Shut it off, put in gear /park and try to rotate the front shaft. It shouldn't rotate. Next you need to look for proper vacuum at the motor and replace lines as required. The switch is a 15.00+/- part and sits on the top of the transfer case. If none of those fix it, I'd suggest the Posi-lok route. Eliminates all of the vacuum operated stuff and replaces it with a cable that you engage when you want 4x4. It works great.