4wd vacuum issues

[Voodoochiled445]

I recently bought an '87 jeep comanche 4.0 and have slowly but surely fixing its issues. Ok so my 4wd light stays on all the time, I'm pretty sure I'm not completely out of 4wd so I replaced the rubber grommet thing that connects the white and yellow vacuum hose to the vacuum motor on my front axle. It worked for a little bit, was finally able to loose traction on the rear tires in the rain, I'm out of 4wd! but as soon as it worked the 4wd light started flickering and now is stuck on once again. I'm getting constant vacuum to the yellow vacuum hose. Now if what I read is correct shouldn't the green hose have vacuum while in 2wd and then yellow in 4wd? I also have constant vacuum on the white hose which I read was for the indicator light. Vacuum to the white hose means 4wd on. right? I'm so confused! haha

 

So I'm thinking I need to replace the vacuum switch on the transfer case but would like some extra help. I can hear the front axle grinding a little bit if I drive in 2wd which has never happened until today.

 

Before anyone suggests the posi-lok I do know about it but can't afford it at this time and would just like to get the vacuums working.

 

Thanks!

[Voodoochiled445]

After reading I'm thinking of just putting the CAD locked in 4wd, I know people say its ok to drive as a daily like this but I have one concern. wouldn't the front and rear wheels move at the same speed? If so wouldn't it shudder while taking turns as a result of the front end moving faster while turning sharp.

 

Thanks in advance.

[garyindiane]

After reading I'm thinking of just putting the CAD locked in 4wd, I know people say its ok to drive as a daily like this but I have one concern. wouldn't the front and rear wheels move at the same speed? If so wouldn't it shudder while taking turns as a result of the front end moving faster while turning sharp.

 

Thanks in advance.

 

The only difference is your front driveshaft will be spining.

It will not shudder because the front and rear will be disconnected via the transfer case.

 

I hope ha get what I'm trying to explain.

 

-Gary

[Eagle]

After reading I'm thinking of just putting the CAD locked in 4wd, I know people say its ok to drive as a daily like this but I have one concern. wouldn't the front and rear wheels move at the same speed? If so wouldn't it shudder while taking turns as a result of the front end moving faster while turning sharp.

No problem. The CAD only locks the right side front axle shaft. Jeep dropped the CAD in the XJ and MJ as of 1991, so all you're doing is making your vehicle the functional equivalent of every new XJ and MJ sold from 1991 onward.

 

The CAD doesn't put the vehicle into 4WD and it doesn't lock the driveshafts. You still use the transfer case to shift into and out of 4WD.

[Voodoochiled445]

Ok gotcha, I'm done with this vacuum issue on the CAD, going to follow a guide i found and get that puppy locked in.

 

Thanks for the replys!

[Pete M]

this one? viewtopic.php?f=9&t=18415

[Voodoochiled445]

Yes that's the one

 

weather is crappy right now (live in washington) but I really need my truck so may just be a trooper and do it in the rain tomorrow haha

 

Any other tips?

[Pete M]

make sure you cap all the vacuum line, or better yet, remove them and cap the source. Otherwise you'll have a vacuum leak. :thumbsup:

[Voodoochiled445]

Thanks for the advice!

 

Ill go through all the steps and should have it done in a few hours tomorrow. This is my second jeep, as you can see in my avatar, Iv also been wrenching on a '78 Cherokee. Getting the hang of these AMCs as Iv mostly worked and built old school chevys. :thumbsup: