'86 CommandTrak not engaging front drive

IdahoJeeper · 12-22-2008, 01:19 PM

HELP!!

It snowed about 7" overnight and after rolling down the driveway, I realized the front drive is not engaged.

Rig is an '86 with the 2.8L V6, 5 speed, xfer case unknown. Transfer case level is (from "top to bottom") 2H 4H N 4L if that helps.

In 4H, the idiot light is lit, and it sounds and feels like the transfer case is engaged but I ended up with rear wheels spinning and the front wheels not doing anything.

The trim on the back of the liftgate says "CommnadTrak". Are the front hubs always engaged or are they activated via some electric means? Any help with this is greatly appreciated as it has continued to snow today.

Thanks in Advance.

p.s. Yeah, I did test it earlier this fall/winter and everything "seemed" to be working correctly.

boredcherokee4l · 12-22-2008, 01:25 PM

Sounds like the vaccum actuator on the front differential isnt engaging.

IdahoJeeper · 12-22-2008, 01:31 PM

Ohhhh, that isn't good.

This thing is a vaccum line nightmare.

Can you shed some light on what I can check to determine if the vaccum is connected correctly? Where is the vaccum source?

boredcherokee4l · 12-22-2008, 01:36 PM

Not sure where the source is. just go to the front diff and look at the back of it believe and there is a square type box bolted to the diff. there should be a vacuum line running to it...thats the actuator...follow the lines up and if there are no breaks, then replace the actuator.

alhefner · 12-22-2008, 01:39 PM

Vacuum to the disconnect motor comes from the transfer case. If you look at your front axle on the passenger side you will see it and the three vacuum lines attached to it.

Put the rig in 4H and you should have vacuum on one of those lines, I forget exactly which one.

I do have one thing here though. Even if the vacuum disconnect was not functioning to engage the passenger side of the front axle, your driver side wheel should be providing something since once the transfer case is engaged, power is delivered to the differential and the driver side does not ever disengage from the axle.

Then again, I could be suffering from massive ignorance here.

IdahoJeeper · 12-22-2008, 01:40 PM

Cool....thanks!!

I'm gunna go check that out right now.

boredcherokee4l · 12-22-2008, 01:41 PM

Quote:

Originally Posted by TX93Cherokee

Cool....thanks!!

I'm gunna go check that out right now.

Good Luck man!!!

IdahoJeeper · 12-22-2008, 01:46 PM

Hey AL....<a bit off topic>...I lived in Reno from '99 - '04 and miss it big time.

alhefner · 12-22-2008, 01:51 PM

Quote:

Originally Posted by TX93Cherokee

Hey AL....<a bit off topic>...I lived in Reno from '99 - '04 and miss it big time.

You left the same year I moved here! Had a really good snow that year.

ksmanimal · 12-22-2008, 03:58 PM

Quote:

Originally Posted by alhefner

I do have one thing here though. Even if the vacuum disconnect was not functioning to engage the passenger side of the front axle, your driver side wheel should be providing something since once the transfer case is engaged, power is delivered to the differential and the driver side does not ever disengage from the axle.

Without the axl shift collar engaged, it would just spin the inner piece of the passenger side axl (just as if one wheel were spinning with no resistance/traction). You wouldn't have power to the driver's side wheel.

IdahoJeeper · 12-22-2008, 04:29 PM

Are the vaccum lines that lead to the transfer case, three in number and yellow, blue and green? If so, they were melted through and disconnected and now I'm thinking they were it.

Shoot.

mctwin2kman · 12-23-2008, 08:04 AM

Yes those are the lines. Red is the source vacuum. Then green is for disengage and yellow is for engage. Yellow should split to yellow and white, white goes to the light switch and the disco, and yellow to the disco as well. You may not have white to the disco due to year of your jeep, my 88 does. Blue is the vent line and is only connected to a filter that looks like a check valve.