'86 Front Differential Not Engaging 4X4

[Comanche_Fanatic]

Its a completely stock 4x4 system, switch gear lever to all places still won't engage 4x4

 

Possible causes?

[cruiser54]

http://comancheclub.com/topic/17377-cad-fix-1/

[Comanche_Fanatic]

I will look into this, if any other possible causes please let me know. Thank you!

[Pete M]

a malfunctioning CAD is by FAR the most likely culprit. :thumbsup: just bypass and fix it for good.

 

other possibilities involve broken parts (snapped shaft, etc). :(

[ParadiseMJ]

First, if you do the CAD elimination it's a.) easy b.) free c.) permanent you'll never have to mess with it again d.) or reversible just in case you are one of the two guys on Earth that don't like it. Eliminating the vacuum system will in no way affect running or driveability. It took me an hour to do it...52 minutes of which was spent cleaning it up, cleaning off the cover, wire wheeling the servo, capping the now needless vacuum lines and laying under the Jeep admiring my work.

 

Its a completely stock 4x4 system, switch gear lever to all places still won't engage 4x4

 

Possible causes?

 

Vacuum lines disconnected, broken, damaged etc. Not the engine vac lines.

 

Get under there and start at the vacuum disconnect servo on the passenger side axle. There is a large rubber plug with 3 (green, yellow, blue) vacuum lines. It's usually filthy and caked with grease. First, make sure it's connected to the axle servo. If it is, follow those lines up to the fender liner where they meet the metal lines. Look for any cracks, splits, holes or wear marks.

 

Then go to the back side of the transfer case and see that the big brass vacuum "bolt" is in good shape and hooked up. Follow those lines too, looking for the same cracks etc. If you have to replace those color coded vac lines, replace them as a unit.