need help with 4x4.
Veteran
Joined: Oct 2006
Posts: 270
Likes: 0
From:
RE: need help with 4x4.
Look at the two connections on your front axle just to the passenger side of the middle of the axle. That is your CAD unit (central axle disconnect).
Your transfer case has vacuum lines coming out of it and traveling to the front axle CAD unit. When you shift your t-case lever into 4wd, the t-case vacuum linesthen operate the CAD which slides a locking collar over the passenger side inner and intermediate axle shafts thus locking them together as one peice and also creating a closed 12 volt circuit that lights the 4wd indicator light. This sliding action of the collar allows for your differential to power the passenger side wheel. Without this action, the power coming out of your transfer case and front driveshaft,would just spinthe spider gears (inside gears of your differential) and no torque would get to either the drivers or passenger wheels.
The most common failure with this type of 4wd system is that the connections on the CAD get hooked on things and become unplugged. Check both the vacuum lines and the 12 volt wires that connect to the CAD unit. If they are connected, follow the vacuum lines back to the top of your t-case and make sure that they are plugged in there as well. If they are plugged in at the top of the t-case, follow the vacuum lines over the back of the t-case and transmission to where they come up into the engine compartment just to the passenger side of the distributer cap. Make sure that the vacuum line has not become disconnected at the "t" in vacuum lines at that location as well.
Your vacuum for the CAD and t-case starts at the "T" connection next to the distributor cap, so that would be the location of origin for the 4wd vacuum.
Good luck, but I'm giving a better than 50/50 chance that the connecions on the CAD have become loose or detached.
If everything checks out with the vacuum lines, it is possible that the CAD unit is malfunctioning. You can check this by removing the 4-bolts that hold it to your axle and having someone operate the t-case lever and watch the CAD and see if it moves.
Your transfer case has vacuum lines coming out of it and traveling to the front axle CAD unit. When you shift your t-case lever into 4wd, the t-case vacuum linesthen operate the CAD which slides a locking collar over the passenger side inner and intermediate axle shafts thus locking them together as one peice and also creating a closed 12 volt circuit that lights the 4wd indicator light. This sliding action of the collar allows for your differential to power the passenger side wheel. Without this action, the power coming out of your transfer case and front driveshaft,would just spinthe spider gears (inside gears of your differential) and no torque would get to either the drivers or passenger wheels.
The most common failure with this type of 4wd system is that the connections on the CAD get hooked on things and become unplugged. Check both the vacuum lines and the 12 volt wires that connect to the CAD unit. If they are connected, follow the vacuum lines back to the top of your t-case and make sure that they are plugged in there as well. If they are plugged in at the top of the t-case, follow the vacuum lines over the back of the t-case and transmission to where they come up into the engine compartment just to the passenger side of the distributer cap. Make sure that the vacuum line has not become disconnected at the "t" in vacuum lines at that location as well.
Your vacuum for the CAD and t-case starts at the "T" connection next to the distributor cap, so that would be the location of origin for the 4wd vacuum.
Good luck, but I'm giving a better than 50/50 chance that the connecions on the CAD have become loose or detached.
If everything checks out with the vacuum lines, it is possible that the CAD unit is malfunctioning. You can check this by removing the 4-bolts that hold it to your axle and having someone operate the t-case lever and watch the CAD and see if it moves.
