Front end will not engage, front drive shaft turning?

Hey guys,

New to this comanche thing, have an '89 shortbox with the 4.0l 5 speed. Just got it running and found that the front axle will not engage. If I put it in 4h or 4l (commandtrac), the front drive shaft turns but the truck doesn't move (rear driveshaft is still off from towing). Can someone get me pointed in the right direction? I want to keep this truck 4x4 selectable.

Thanks

Your CAD isnt working right..ie, the disconnect is remaining disconnected, and not connecting ;)

Where is it and how do I fix/test it?

Its on the passanger side of the front axle, on the back of the tube (almost under the starter). Its a vaccume acctuated motor that slides a collar over the splines of the two shafts and engages them. You might have a sticky shift fork, or a broken vaccume line. You can take out the 4 bolts on the vaccume actuator to see if it is sticky. If it moves fine then you have a vaccume problem :(

The way I see it is that you have 4 options.

1) Fix the problem. It could be a sticky shaft, or a vacume problem. They are very temperamental and in the past I have not had much luck with them.

2) Buy the cable actuated part. Runs you around $175. This eliminates the vacume and makes it so you can move the selector fork via a cable.

You could also make your own using a cable from a lawnmower or bike cable.

3) Move your selector fork over perminatly. This can be done by tearing apart the CAD and putting washers/spacers/whatever behind the fork to keep it moved over perminatly. Doing this makes your DS spin while driving like the 91+ models. You than simply select your 4WD via your transfer case.

4) Remove the 2 piece shaft and put in a 1 peice shaft from a later non CAD axle. You than simply remove the CAD and make a plate to cover the hole.

I've opted for #3 on my vehicals. You just need to make sure you get the fork over far enough. The farther over you can get it, the better.

Here it is You will find it just under and behind you pass side front tire...

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Here it is loooking thru the pass side wheel opening:

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In the pic above, I was having simular problems to yours. I decided to run all new vac lines. You can see the rubber lines in the pic. the factory stuff is plastic and colored. You can see that in my first pic.

Post above shows you what the inside is like. Its just a "fork" that moves a "collor" to connect the inner and outter axle shafts of the pass side.

Here is a great site for maintaince as well as upgrade projects!!

http://gojeep.willyshotrod.com/

CW

once it's removed you can blow into the vac line openings and see if the shift fork moves.

use your hand on the shift fork to offer a little bit of resistance...the vac. actuator could "work" but have a small crack in the membrane inside that won't allow it to work under resistance.

Thanks for the help guys. Now I have an idea where to go next. I'm sure I'll have more questions before I'm done. Just finished a CJ-7 and had the itch for another Jeep project, glad my wife loves me :brows:

Here it is You will find it just under and behind you pass side front tire...

 

Image Not Found

 

 

Here it is loooking thru the pass side wheel opening:

 

Image Not Found

 

In the pic above, I was having simular problems to yours. I decided to run all new vac lines. You can see the rubber lines in the pic. the factory stuff is plastic and colored. You can see that in my first pic.

 

Post above shows you what the inside is like. Its just a "fork" that moves a "collor" to connect the inner and outter axle shafts of the pass side.

 

Here is a great site for maintaince as well as upgrade projects!!

 

http://gojeep.willyshotrod.com/

 

 

 

CW

Nice link CW

I did the cable mod using an engine throttle cable from a cherry picker. Works nice every time.

x2 on the great link. that site should be stickied in a thread with other mj/xj technical topics. ;)

I did the cable mod using an engine throttle cable from a cherry picker. Works nice every time.

???

Here in Ohio, a "cherry picker" is how we refer to an engine hoist.

Since an engine hoist definitely does not have a throttle cable, what is it that's called a cherry picker in your part of the woods?

I did the cable mod using an engine throttle cable from a cherry picker. Works nice every time.

 

???

 

Here in Ohio, a "cherry picker" is how we refer to an engine hoist.

 

Since an engine hoist definitely does not have a throttle cable, what is it that's called a cherry picker in your part of the woods?

Cherry Picker = ?

I did the cable mod using an engine throttle cable from a cherry picker. Works nice every time.

 

???

 

Here in Ohio, a "cherry picker" is how we refer to an engine hoist.

 

Since an engine hoist definitely does not have a throttle cable, what is it that's called a cherry picker in your part of the woods?

That's what we call it here in Cheap Jeep country too.

i thought engine hoist at first but almost instantly infered that an engine hoist does not have a throttle cable and thought of what a true cherry picker is, its not rocket science :nuts: .

I did the cable mod using an engine throttle cable from a cherry picker. Works nice every time.

 

???

 

Here in Ohio, a "cherry picker" is how we refer to an engine hoist.

 

Since an engine hoist definitely does not have a throttle cable, what is it that's called a cherry picker in your part of the woods?

 

Cherry Picker = ?

an another note, if this were rigged right, i suppose it would work as an engine hoist. :evil:

My mistake, I meant something along the lines of this:

Older cranes use a mechanical throttle cable to speed up the engine and hold it at a certain rpm. It's like a heavy bicycle cable, that's all.

My mistake, I meant something along the lines of this:

 

It's a little cumbersome, but I guess it could hoist an engine...

My mistake, I meant something along the lines of this:

 

It's a little cumbersome, but I guess it could hoist an engine...

I doubt it. Way too much weight for something that size.