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Diagnosing 4x4?


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Hey guys

 

I wanted to know how do you diagnose 4wheel drive...I mean I tried putting my truck into 4wd but idk if it works I tried messing with some loose dirt but I don't think the front axle is in 4wd....or could it be the command trac? Could anyone lead me in the right direction...sorry first jeep and 4x4 still trying to learn the kinks before I really go crazy and get stuck somewhere when the truck is ready for off roading

comanche.gif :wrench:

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4wd is controlled by your t-case. all the CAD mod does is make your Jeep like any later Jeep. They got rid of the silly thing in the early 90s. :thumbsup:

 

The only possible downfall is that if your front driveshaft has a bad U-joint, you'll know it. Not really a bad thing though, since you should replace a bad ujoint anyways.

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If your t-case lever shifts okay, chances are it's shifting into 4wd okay. If you don't get some jerking in the front when turning tight on a dry surface, chances are the vacuum disconnect in the front axle is not working properly.

 

A free and easy fix is to remove the shift fork from the front axle (4 bolts), slide the shift collar to the locked position, and reinstall the shift fork upside down to hold the shift collar engaged. Now you will have 4wd for sure.Test on loose gravel.

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2 ways. find loose dirt like, dusty stuff. put in 4wd... either lean out the window and look right behind the tire or have a friend who has a brain watch for you. mash it and look for a little upset in the dirt. If the wheel isnt being powered the dirt will be smooth/undisturbed.

Also you can drive up a steep incline thats covered in loose dirt/gravel. when you start spinning the rears and can't go.... you then back down... engage 4wd and try again. Now you go right up? its workin. :)

 

I like the comment someone made about the lurching.

If you put it in 4 low and then turn around you will know its in 4wd. the truck will hunch up and buck. Cause this transfer case doesnt have a diff in it like some do. Its full lock when its on.

I call it "hunchy". lol

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Does that allow the diff to be full time 4wd or temp like when I go offroading?

If you have a Comanche, you do not have a full-time option unless a previous owner has changed the transfer case. DO NOT drive it in 4WD on dry pavement.

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Correct, the transfer case shifts from 2wd to 4wd with the lever, sending power to the front driveshaft.

 

The vacuum system only connects a 2-piece axleshaft on the passenger side of the front axle when the transfer case is shifted to 4wd.

 

Your Jeep will act as if it's in 2wd if the vacuum disconnect is not engaged, as the power through the front driveshaft will go to the axleshaft with the least resistance, which is the disconnected passenger side.

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Ok so when I do this procedure the only time itll be in 4wd if I chnge it from the transfercase lever right? So that when its in 2wd the transfercase is not moving....

Not quite.

 

Locking the front axle disconnect means that the front driveshaft will always rotate when the front wheels are turning. This means that some of the parts inside the transfer case will also be moving ... BUT, they won't be connected to the rear section of the transfer case or to the engine, so they just sit there and spin, they don't do any work.

 

When the transfer case is shifted into 4WD, then the front and rear are connected together and power is delivered to both the front and rear driveshafts.

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Just a question, can the truck be placed on jack stands, started, placed in 4WD and see if the front wheels rotate? If they don't check if the front shaft rotates.

Or will this not work and/or cause damage? I also don't know much about 4WD.

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No need to get that crazy. You just need to jack up the passenger front tire. Fire up the truck (so there's plenty of vacuum), and shift into 4wd. if the CAD is engaged, the tire won't spin. if the CAD is disengaged, the tire will spin freely. :thumbsup:

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Does that allow the diff to be full time 4wd or temp like when I go offroading?

If you have a Comanche, you do not have a full-time option unless a previous owner has changed the transfer case. DO NOT drive it in 4WD on dry pavement.

 

86 had a full-time option with the 228/229.

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