Squealing / squeaking noise coming from transfer case are

Lifted straight six

TJ Enthusiast
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arizona
Another issue has occurred in my drivetrain(90% sure). I’ve noticed recently that after longer drives, 15 miles or so i get a faint squealing/rubbing noise at low speeds. It doesn’t happen after short drives, and if i turn the jeep off for about 5 minutes and get back in, it stops again. Only happens when moving and sounds like it’s coming from the transfer case area. I have an np231 with SYE and recently rebuilt tom woods rear drive shaft.
 
The front driveshaft has a DC (aka CV) joint that can sound like "angry birds" when it's going out. It's adjacent to the transfer case so that's a possible source of the squeaking.

I'd temporarily remove the front driveshaft to see if the noise goes away. If it's the front driveshaft's DC joint that is squeaking you can't delay fixing it. If the DC joint seizes it will take the entire transfer case out with it. As in the tcase can literally explode when the DC joint has seized.

Or you can temporarily just unbolt the front of the front driveshaft from the axle and support it up out of the way to see if the noise goes away.
 
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The front driveshaft has a DC (aka CV) joint that can sound like "angry birds" when it's going out. It's adjacent to the transfer case so that's a possible source of the squeaking.

I'd temporarily remove the front driveshaft to see if the noise goes away. If it's the front driveshaft's DC joint that is squeaking you can't delay fixing it. If the DC joint seizes it will take the entire transfer case out with it. As in the tcase can literally explode when the DC joint has seized.

Or you can temporarily just unbolt the front of the front driveshaft from the axle and support it up out of the way to see if the noise goes away.
I will be sure to check that out. You think that would make noise after awhile of driving? If the jeep is fresh off of a cold start it won’t make the noise until after about 20 minutes(12-15 miles) of drive time. I also have a light squeak from the output shaft seal in my SYE but i’m pretty sure that these 2 are completely different squeaks.
 
I will be sure to check that out. You think that would make noise after awhile of driving? If the jeep is fresh off of a cold start it won’t make the noise until after about 20 minutes(12-15 miles) of drive time.
The front driveshaft spins all the time while driving, even in 2wd. It could be caused by the DC joint heating up from a lack of lube etc..
 
The front driveshaft spins all the time while driving, even in 2wd. It could be caused by the DC joint heating up from a lack of lube etc..
This makes a lot of sense. Will be sure to disconnect that tonight and let you know tomorrow on my drive to work if the noise changed. I appreciate your input jerry, always a big help.
 
The front driveshaft spins all the time while driving, even in 2wd. It could be caused by the DC joint heating up from a lack of lube etc..
So, i tried your advice, took it for a drive tonight with front driveshaft tied up and no change in the noise… it did help my vibes a little bit, but the noise is still a loud screeching type noise, almost sounds like a leak in the evap system, but i can almost promise that isn’t the issue, as it is only prevalent while slowing down or going low speeds. also could say it kinda sounds like crappy brakes, has that whistley creaking type noise. any new advice? i do have a double cardon tom woods in the rear, even if it’s rebuilt do you think maybe the centering ball could be bad?
 
Check the rear shaft as well. For this you will need to completely remove the rear shaft. Reconnect your front and drive around in 4 wd enough to test for noise. While the rear shaft is out you can flex the u joints and inspect for any play or unusual tightness In The joints.
 
Check the rear shaft as well. For this you will need to completely remove the rear shaft. Reconnect your front and drive around in 4 wd enough to test for noise. While the rear shaft is out you can flex the u joints and inspect for any play or unusual tightness In The joints.
I just had driveshaft rebuilt not even 1,000 miles ago, and i’m not getting any type of weird vibrations, you still suggest it to be rear DS? i just figured out my front pinion seal on my dana 30 is leaking a little bit, and that seal is brand new.. that wouldn’t cause a squealing/creeking type noise right?
 
It may not be the rear shaft. Just trying to eliminate sources. Does it go away if you apply the brakes?
 
Not that i’ve noticed, i’m going to attempt to get a video tonight on my way home from work, when i try to recreate the noise
A great but not super safe feeling way to troubleshoot it is to get the vehicle hot to where it starts squealing and put up on jack stands so you can "drive it" still then crawl under and find where it's coming from. Check that your rear TC output has lubrication, get it squealing then spray some oil right there. If its a starved seal thing it will go away. Also retorque the yokes on both TC outputs.
 
A great but not super safe feeling way to troubleshoot it is to get the vehicle hot to where it starts squealing and put up on jack stands so you can "drive it" still then crawl under and find where it's coming from. Check that your rear TC output has lubrication, get it squealing then spray some oil right there. If its a starved seal thing it will go away. Also retorque the yokes on both TC outputs.
What “oil” do you recommend? Ive heard white lithium grease is best for this type of stuff, but i’m not totally sure
 
What “oil” do you recommend? Ive heard white lithium grease is best for this type of stuff, but i’m not totally sure
To start I'd just put ATF on it. If it goes away pull the yoke and add some grease. I used some really thin grease I had from mountain bike forks that's ok for orings. Not sure if WL is okay or not.
 
To start I'd just put ATF on it. If it goes away pull the yoke and add some grease. I used some really thin grease I had from mountain bike forks that's ok for orings. Not sure if WL is okay or not.
Yeah, white lithium is about the only “liquid” that will actually do something good for seals, i will try ATF, and a little bit of white lithium grease, i’m also going to grease my centering ball. let you know how that works tomorrow.
 
Yeah, white lithium is about the only “liquid” that will actually do something good for seals, i will try ATF, and a little bit of white lithium grease, i’m also going to grease my centering ball. let you know how that works tomorrow.
Just remember to do only one thing at a time. Oil on seal then retest, then if that doesn't work check yoke nut torque values. Interested to hear results. Good point on centering ball, you can imagine if that were dry that could make a squealing also.