Designated Decoy

I'm brand new here and hopefully this is the place to post this but I am getting worried in a time crunch so if this is the wrong place to post feel free to send me elsewhere!

I've been trying to figure out a popping or grinding noise that is coming from somewhere in the undercarriage that just suddenly got worse after pulling a motorcycle trailer for about 9 hrs. A lot of my searching hasn't found this specific problem so here I am. At first the noise sounded like it was coming from the rear end, so an axle or diff problem but I got some help to start the car up while I was under it and it seems to be coming from the tranny/tcase region but I just can't pinpoint it with the engine noise. I've never been able to easily replicate the noise when I needed to diagnose it, but now it happens a lot and is louder especially when the weather is cold. It happens the moment I start the up sometimes, just 1-3 pops then stops. Nothing when I shift into gear, but when I back out and turn I hear it again, still inconsistent. Same for pulling forward, and most likely when I make a left turn is when it gets the worst. Haven't had the environment to get into checking fluids or pulling parts and taking it to the local jeep guy is gonna cost me money I don't have just yet so I gotta narrow this down and hopefully get it right the first time before something big goes, that is if it isn't something I can do with my basic tool set. Any expertise would be greatly appreciated!

Thernlund

It almost sounds like you have something free in the gearbox. Maybe some gear teeth broken off and moving around loose in there?


-T.

Designated Decoy

I hope not... I'm guessing that would require a tranny rebuild?

Designated Decoy

So I tried a trick I saw elsewhere on here with throwing it into 4wd and pushing the engine into the brakes and that did cause a ratcheting noise, so I think the transfer case might be shot. THe weird bit was that I smelled an almost sulfur like smell immediately after I stopped, which is the second time that has ever happened (Last December being the first time) so that is weird.

TRCM

sulfur smell could mean slipping clutch or brakes

Suprmn

Well, not exactly sure on this one based on your description, but the first thing I would look at is the chain in the transfer case. you might put it up on jack stands and then turn the rear driveshaft while listening right at the transfer case. I have seen the chains worn enough that they are dragging on the case. Then the popping is when it jumps a tooth. Not positive on this one, but a place to look.

Designated Decoy

Yeah unfortunately that's all the info I can give which has been the problem I've had with identifying it. I was told water in the transfer case could cause the smell, but was also told that since it is happening in 2wd not just in 4wd means that it's more likely the transmission than the T-case. I dunno, I'll just have to get my bike ready to go then garage the jeep and start pulling parts..