Engine/Transmission (1998.5 - 2002) 4 Wheel Drive Problem

[gahorn]

Went out this morning fired the truck up and started down the road with the intent of going back in the woods to move some firewood. When I went to put the truck in 4-wheel drive (woods is very wet); it felt like it went into gear but the indicator light didn't come on. I backed up several feet thinking maybe it wasn't going in due to bind, but still no light. I went off road into the ditch & tried to spin the tires to see if it actually was in 4WD and discovered it wasn't -- only spun the back tires. Went back home & crawled under the truck, checked out the vacuum lines and everything appeared OK. Went back out & tried again but no luck. Any suggestions?



Thanks everyone

Gary

 

[Spunkys Ram]

The light is triggered by the CAD on the front axle which is vacuum controled by a switch on top of the T-case. The switch receives it vacuum from the main line that runs across the top of the firewall. I would check all the connections from the vacuum pump to the switch and front axle. Make sure there are no breaks/cracks. Most likely cause is the vacuum switch on top of the T-case. Hope this helps you out.

 

[gahorn]

Spunky-- Thanks for the advice. I'll trace this out this weekend and hopefully find something simple. Can that switch, if bad; be bought somewhere on line any cheaper that from the dealer? How do you know if the switch is bad versus something in that part on the front axle? Any tips on how to diagnose would be greatly appreciated.



Thanks



Gary

 

[Moose Truck]

How's the heater controls, and the cruise control? The to operate of off that vacume line. If the line is disconected off of the pump (Hapened to me. ) or the pump is dead none of that stuff will work. Moose.

 

[PDeverney]

just worked on one of these. verified vacuum to front diff actuator was switching by unpugging it and running engine. ended up being bad vacuum actuator.

 

[gahorn]

Moose -- Thanks for the reply. The cruise control and heater controls work fine.

PDeverney --Thanks for answering. Just want to make sure that I got this right. Disconnect the vacuum lines at the actuator valve on the front axle & start the engine. Should I feel a "draw" on the hose if I place my finger over the end?



Thanks for the help



Gary

 

[PDeverney]

yeah, i believe its the red line(closest to pass side tire) when in 2wd. switch it to

4wd and other line should have vacuum to it. that would verify that vacuum to

t-case switch is there and switch is working. if that all checks out ok then more than likely actuator is bad. i bought one from local dealer for around 200. 00. there might be less expensive ones out there but i didnt have time to shop. good luck, pete