I took my 89 renix XJ 4.0L 4x4 mudding last week. i got stuck in VERY deep ruts however if my 4x4 was working, i would have been able to get out. With 4x4 on part time and full time, the wheels appeared to "try" to move, they were hesitating. I looked up the vacuum thing, however i couldnt find any or CAD? i dont know much about 4x4 or axles, please help!

 

oh and my 4x4 "shifter" feels very weird, its hard to change and to put back into 2wd, it has problems going to 4lo if that helps

 

It could be the vacuum disconnect, yours should have it.

It'll be right near the passenger side upper control arm, on the back side of the axle.

 

Oh, does 4 low engage at all?

 

First 2 things I would check is your linkage to the transfer case, and do a diff fluid change....

 

mine doesn't have the vacuum thing under the upper control arm, i thought all renix Xjs would have that on the Dana 30? maybe mine is rare or someone swapped it? since it hestitates on every option, im not entirely sure if 4lo works, i do know it makes a bad grinding sound so ive only ever tried it twice. would a diff fluid change really help? i mean it sat for 4 years and who knows the last time its been changed but still. and what should i check on the linkage, bushing? readjust?

 

It could be a bad tcase or linkage out of adjustment. Have someone shift while you examine the linkage under the truck.

My linkage was bad, but that wasn't my problem. The chain had stretched.

 

Well, a diff fluid change would get you inside to inspect whats going on...and if it sat for a long time, and you like the wet stuff, you should be doing this anyways. It's an easy job you can do yourself. It could be your tcase, but check the easy stuff first.

 

what should i inspect? metal shavings, broken parts? Sorry this is the first time i work on an axle or diff. I hope its not my tcase, it was a mail jeep never taken offroad (i believe) and i hope the chain isnt stretched or anything. I will also inspect the linkage

 

Yeah look for shavings/broken teeth, pieces of shim, etc.
One thing I can suggest is to get a Factory Service Manual for your year, make and model. NOT a Chiltons/Haynes manual, you can get them online in a PDF format for around $5-15.00, it's what they use at the dealerships and has everything you could want as far as info goes, torque values, and so on. Your XJ will thank you, LMAO

 

haha alright, thank you all so much for the help!