Popping slipping noise under heavy wheeling

robhurlburt · Apr 4, 2011

This past weekend i got into some stuff that i had to be pulled out of. First time this has happened in the XJ. When i would get in some heavy rock gardens, and I would hit it hard, there was some popping noises. One guy said it was normal, one guy said maybe the chain was slipping in the t-case. Both of them said to not worry about it.

What could cause this?

95 sport, NP231, 3.5in lift, 31s

Tim_MN · Apr 4, 2011

robhurlburt said:
.....hit it hard, there was some popping noises. ....What could cause this?

Where did the noises come from ?

Both those guys are wrong, that is not a usual Cherokee noise.

A slipping T-case chain would be the most likely suspect.

kastein · Apr 4, 2011

Where did the noise come from? Front, middle, or rear?

Rear probably means spider gears in the rearend, not something you want to ignore. Middle probably means t-case chain, also not something you want to ignore. Front means spiders in the frontend or perhaps U-joints... still not something to ignore!

Pull the fill plug on your case and 1. make sure it's got enough fluid 2. use your finger to check chain tension. If the chain is real loose and floppy you need to open the case and at a minimum replace the chain, depending on how long it's been like that it may have worn the inside wall of the housing and/or chewed up the sprockets as well.

robhurlburt · Apr 4, 2011

kastein said:
Where did the noise come from? Front, middle, or rear?

Rear probably means spider gears in the rearend, not something you want to ignore. Middle probably means t-case chain, also not something you want to ignore. Front means spiders in the frontend or perhaps U-joints... still not something to ignore!

Pull the fill plug on your case and 1. make sure it's got enough fluid 2. use your finger to check chain tension. If the chain is real loose and floppy you need to open the case and at a minimum replace the chain, depending on how long it's been like that it may have worn the inside wall of the housing and/or chewed up the sprockets as well.

i want to say middle to front. i am going to change the diff fluid, so i can check the gears when i do that. also, if it is a loose chain and it is rubbing, wouldn't i hear it all the time?

robhurlburt · Apr 5, 2011

does anybody have a good DIY for replacing the transfer case chain?

robhurlburt · Apr 6, 2011

drained and filled the fluids in the diffs and transfer case. diffs looked fine, transfer case was damn near bone dry and the chain was loose. must be the chain popping.

jonathanlo · Apr 6, 2011

That's what happened to mine a couple years back. Turned out I tatered the tcase chain. Now it's doing it again after a tcase rebuild about 20k miles ago. Mine initially messed up because I had the wheel turned too far when i hit the gas really hard (I was stuck)

Matthew Currie · Apr 6, 2011

I hope before you dig into the transfer case you check carefully that the front axle u-joints are all right. That's the most common source of odd noises when running in 4WD.

robhurlburt · Apr 6, 2011

Matthew Currie said:
I hope before you dig into the transfer case you check carefully that the front axle u-joints are all right. That's the most common source of odd noises when running in 4WD.

what am i looking for when i check the u-joint?

Matthew Currie · Apr 6, 2011

robhurlburt said:
what am i looking for when i check the u-joint?

Looseness and binding. You can get a good idea of looseness just by getting under and wiggling the joint. If it wobbles or rattles, it's bad. You can get a better idea if you jack a wheel (or wheels) off the ground, and rotate the wheel. If there's lost motion or if it rattles, clanks or binds, it's bad. Turn the steering all the way in either direction and rotate the wheel to check for binding. The joints will often get stiff first, and then after a while they'll wear further and get loose. When they get bad enough they will sometimes wrap up a bit and then let go, giving you the popping noise in 4WD.

robhurlburt · Apr 7, 2011

i was under there tonight pulling yanking and cranking on it and it seemed fairly tight. nothing that made me go hmm...

i am going to order a chain tonight, it seems like a straight forward install

sdspearo · Apr 7, 2011

Kastein mentioned earlier to check the chain tension thru the fill plug hole. When you do this, how tight should the chain be? i.e., 1/8" slop, or what? What's normal tension?

robhurlburt · Apr 7, 2011

sdspearo said:
Kastein mentioned earlier to check the chain tension thru the fill plug hole. When you do this, how tight should the chain be? i.e., 1/8" slop, or what? What's normal tension?

thats a good question, and i wish i knew the answer. i could stick my finger in-between the sproket and chain. seemed too loose to me

kastein · Apr 7, 2011

Not sure honestly, mine went from fine to bagged as hell in less than a day when my rear output seal blew and all the fluid came out before I got home. I can tell you that a case we SYE'd for a friend last weekend (and installed a brand new chain in) had about 1/8" to 1/4" of rotational play (measured at the outside of the yoke) on the front output with the rear output and the input shafts locked in place.

The fact that it's skipping teeth (probably) and making noise tends to indicate it's got too much play... way too much. I'd be curious how much you can rotate the front output with the vehicle in park, 4x4, and the front shaft dropped.

robhurlburt · Apr 7, 2011

kastein said:
I'd be curious how much you can rotate the front output with the vehicle in park, 4x4, and the front shaft dropped.

in park last night i could rotate the front shaft maybe a 1/4in.

kastein · Apr 7, 2011

Your front axle was probably limiting rotation - did you have the driveshaft connected to the axle or no? Wheels off the ground or on?

robhurlburt · Apr 7, 2011

kastein said:
Your front axle was probably limiting rotation - did you have the driveshaft connected to the axle or no? Wheels off the ground or on?

thats correct. on ground, in park, 2WD. i could move the jeep by turning the axle. when i go to replace the chain, i will update on how much it moves.

Should i jack it up and put it in 4WD and see how far it will turn?

kastein · Apr 7, 2011

Jack the front end off the ground and put it in 4wd - see how much it turns then. Alternatively drop the front driveshaft and put it in 4wd.

Popping slipping noise under heavy wheeling

robhurlburt

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