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stuck in 4wd


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so i drive 5 hours to pennsylvania to buy my 1988 mj 4.0 auto shortbed mj. i get there it looks decent so i load it on the flatbed. while my buddy is strapping it down he realizes there is no front driveshaft. the p.o. says it got stolen a while ago. i didnt make it into an issue because i had two back at home. so today i decide to bolt on the frnt dshaft. it doesnt shift out of 4wd. the lever deffinetly feels like it goes into 2wd but the indicator light stays on and frnt and rear axles are getting power. any ideas? i don't know where to start.

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The light is turned on from the cad...it could be sticking. The later models T-case used a sensor in the TCASE for the light...not you year. So its quite likely the 4WD is going in and out..only the light is showing its still in 4WD.

 

I would do as others have suggested, jack it up and MANUALLY check!!

 

CW

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sounds like if he spun front and rear tires on dirt... that there's no second guessing it's in 4wheel.

 

you can't spin front tires without power to them... right? :nuts:

 

you could pull the rear shaft and see if itll move if you want a test without jacking it off the ground.

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Vacuum controls ONLY the axle disconnect. If the transfer case is in 4WD when the lever says 2WD, either the linkage isn't adjusted correctly or there are problems inside the t-case.

 

Given that the seller apparently knew there was a problem and lied about the driveshaft to cover it up, I think you are safe to bet the problem is inside that transfer case.

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damn previous owners. :headpop: as if the bondo'd over spray foam body filler wasnt enough. u guys think i should believe his story about the odometer cable breaking the previous week to me buying it? and he says it needs an exh manifold but theres one in the bed that hes willing to give me. he doesnt mention its for the chrysler head and that it also has a crack. good thing ive got a spare tcase around here

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Vacuum controls ONLY the axle disconnect. If the transfer case is in 4WD when the lever says 2WD, either the linkage isn't adjusted correctly or there are problems inside the t-case.

 

not sure if this is relavant, but i unplugged the vaccume hoses from the back of the transfer case, and lost fuel pressure. plugged them back in, and i had pressure.

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Vacuum controls ONLY the axle disconnect. If the transfer case is in 4WD when the lever says 2WD, either the linkage isn't adjusted correctly or there are problems inside the t-case.

 

not sure if this is relavant, but i unplugged the vaccume hoses from the back of the transfer case, and lost fuel pressure. plugged them back in, and i had pressure.

Okay, ya got me.

 

Vacuum does control more than the axle disconnect. But -- nothing inside the transfer case, so a vacuum problem could not result in the t-case staying in 4WD. That's what I was trying to say.

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From my experience below, I learned that once the vacuum disconnect is fully engaged then vacuum is connected to the indicator switch. The light only indicates that the right front axle is powered. The transfer case is a good faith operation.

I got a real mystery on that vacuum disconnect. I have an 86 Cherokee from new with Command trac. All worked fine for years. Gradually, it took more to disengage the front axle. First slow down, then stopping, and then reversing. One night I took it out of 4wd and as ususal the front axle was still engaged. Before I had a chance to pull over to back up, there was a WHAM. Next time no 4wd. I took out the disconnect and it was jammed in the off position. Forced it back into place and it operated properly, so I put it back together. Next time I needed 4wd, nothing. After studying the vacuum circuit and watching what does what, I ended up pulling two of the vacuum lines out of the plug at the axle and reversing them. Now it works fine. ???????????

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From my experience below, I learned that once the vacuum disconnect is fully engaged then vacuum is connected to the indicator switch. The light only indicates that the right front axle is powered. The transfer case is a good faith operation.

I got a real mystery on that vacuum disconnect. I have an 86 Cherokee from new with Command trac. All worked fine for years. Gradually, it took more to disengage the front axle. First slow down, then stopping, and then reversing. One night I took it out of 4wd and as ususal the front axle was still engaged. Before I had a chance to pull over to back up, there was a WHAM. Next time no 4wd. I took out the disconnect and it was jammed in the off position. Forced it back into place and it operated properly, so I put it back together. Next time I needed 4wd, nothing. After studying the vacuum circuit and watching what does what, I ended up pulling two of the vacuum lines out of the plug at the axle and reversing them. Now it works fine. ???????????

 

On my XJ it's always been finicky about engaging that front disco also, normally I'd just pull a line off, then plug it back in & everything would be fine. Yes, the light only seems to indiicate that the vacuum disco axle is functioning "correctly". Recently my light has stayed on all the time even though my axle disconnects....

 

Last night we finished installing a 4wd conversion on an XJ. We used an MJ disco D30 on a 91 XJ (no vacuum operation).

We fixed the front disco axle by doing the following:

Remove shift fork assembly from axle (catch grease)

Remove c-clip from rod on side of fork away from vacuum diaphram.

Slide fork over & slide rod opposite way (towards diaphram) until you see the c-clip's notch on the rod again.

Replace c-clip in notch.

Shift fork cannot move now.

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