2nd Gen Non-Engine/Transmission no four wheel drive

[LHastings]

This morning it was snowing and I went to put it into 4 wheel drive the light came on but iit felt it was only three wheel drive. Where does the 4X4 indicator light get it signal? Does it come from the axle or transfer case? If it come from the axle what could hold it from locking the axles if the light comes on.

 

[JGheen]

I wouldn't worry about the light, it will always come on even if the 4x4 doesn't work. I had the same thing happen to me a couple times. You have a vacuum leak somewhere that is causing the CAD(Central Axle Disconnect) to not engage. The most common place I have seen leaks is around the CAD housing on the axle. Check to see if the black and red plastic hard lines going to the housing are connected to the vacuum port. If it's good there, follow the lines up to the frame and back towards the front of the transmission/transfer case mount, they could also be leaking there.

The best option to get rid of the vacuum actuated CAD is to replace it with a 4x4 Posi-Lok. I just recently put one in and I feel much better about being out in the middle of nowhere and not have to worry about any vacuum lines leaking since the CAD is now manually operated. I can even run the truck in 2WD low. Oo.

 

[vssman]

The 4x4 signal should come from the CAD. I thought the light would only come on when the CAD moved the shift fork in the front axle to engage it. To be sure, I'd engage 4X4 and wait for the light to come on. Shut the truck off and try to spin the front driveshaft by hand. It shouldn't move. Next I'd push the lever back to 2wd. Get under the truck and try to spin the front driveshaft. I think that may tell you if the front end is locking (as long as the CAD doesn't release the front axle when you shut it off - which it shouldn't).

 

[nutter3]

LHasting,

Unless you have installed a locking front differential, you will never have "true 4x4". At best you have 3 wheel drive with a limited slip in the rear.

I think the 4x4 light is operated from a switch in the CAD. Someone please correct or verify this please.

 

[jrobinson2]

The switch for the 4x4 light is in the CAD (center axle disconect) I have however, seen trucks that would turn on the light before the CAD engaged properly, leaving you with a 4x4 light but no 4x4 axle.



Jared

 

[LHastings]

When it warm up i'll crawl under it and check it out. This morning was not fun, allot of ice under the snow. The posi lock looks good. With the posi lock can you lock the axle when your off road and shift the tranfer in and out when you need to. The posi lock site says to ingage the transfer first then lock the axle. The front axle is not a locking diff just a standard hypoid.