Popping noise from front or middle of Jeep

Sounds like it's either the front diff or the t-case. It only occurs in 4wd and when I am giving it gas. The sound is almost like a stretched chain that's slipping on the teeth or something. Is that a possibility? Would that only happen in 4wd or would be all the time.

I swapped the front drive shaft out with one from a lower mileage XJ and while it was in better shape, the noise continued. I was hoping maybe it was a bad u-joint on the shaft.

96 XJ 4.0/AW4/231, HPD30 with 4.88s, 33s, D44 rear with Detroit, 166k miles, crappy paint...um, I think that covers all the bases...

Yes a stretched chain would make some sweet popping noises in 4L (or even 4H).

Try doing a brakestand in 4L and see if it continues to pop while standing still. I know this is putting undue stress on the components but it might help you narrow it down.

Other than that, I would pop the front cover and take a look.

Mine used to make a noise in 4wd on the gas, it was a bad popping, ended up being a loose track bar bracket.

Have you checked the bolts holding the transfercase to the transmission?
Years ago while in Moab I was hearing a similar sound and during troubleshooting the problem you could see the transfercase torqueing over. The bolts holding the transfercase to the transmission were loose.... I removed one at a time and applied blue loctite and then snugged them down. Been fine since.

I had a similar sound that was due to some broken spider gears, but it would also bind up a little on some corners. It is at least worth popping the diff cover and taking a peek. That would be an easier fix than a transfer case chain.

If you take the shaft out, you can narrow it to the front diff or the tcase.

If the noise stops, you know your front axle is good. If you put it back in and the noise comes back, you've got something in the tcase or the shaft.

Do you have stock suspension (not stock, but the mounting points) or something long arm?

RedHeep said:

If you take the shaft out, you can narrow it to the front diff or the tcase.

If the noise stops, you know your front axle is good. If you put it back in and the noise comes back, you've got something in the tcase or the shaft.

Do you have stock suspension (not stock, but the mounting points) or something long arm?

Click to expand...

If you take the shaft out and the noise stops it could be in the diff. You already established that it's not coming from the shaft. The t-case chain can't slip in 2WD. I would put it in 4HI and rotate the front driveshaft back and forth by hand. It shouldn't rotate more than about 1/8 turn, if it does then the chain is probably stretched.

RedHeep said:

If you take the shaft out, you can narrow it to the front diff or the tcase.

If the noise stops, you know your front axle is good. If you put it back in and the noise comes back, you've got something in the tcase or the shaft.

Do you have stock suspension (not stock, but the mounting points) or something long arm?

Click to expand...

RK 3 link.

I'll try pulling the shaft again and brake torquing it in 4wd to see if the noise is still there. If so, I'll probably leave the shaft out and order a rebuild kit when I have money, maybe a wide chain and a 4:1 since it'll be torn apart...then, I may just drive down and make you guide me through the rebuild process, John.