Jeep Cherokee NP231 Transfer Case Noise Solved!!!

Diagnosing some drivetrain noise out of my NP231 transfer case in my 1992 Jeep Cherokee XJ. Note - I have a slip yoke eliminator.
Initial problem: I’d get a loud whine only upon acceleration throughout my speedometer. Put it up on jack stands heard some inconsistent not very loud teeth on teeth sounds out of my T case. Took out part and contacted Advance Adapters to get their take on it. I’ll let you guys know what I find.
Solution: I eliminated the grinding noise by changing the thickness of the main gasket: when re-assembling the case halves, I let the permatex liquid gasket maker cure for an extra hour before tightening the bolts up to torque spec. This provided enough clearance in the case for the gears to have just a tad more room. It's interesting how the thickness of the gasket can actually change the clearance of the gears in the case. Good luck and subscribe! :)
Blog: cedricsworldblog.wordpress.com

[@ttv_saltyshooter1804]

I got a 89 jeep cherokee xj front end is popping and grinding was stuck in 4 i believe so removed driveshaft any more information on it would be nice because it was locking up my turn and previous owner insta one now its making noise in the frint

[@doublebasserrazzmuss2408]

Hello. '08 5.7 Jeep Commander. My transfer case sounds/feels like its binding up the two driveshafts. any suggestions? thank you for your time.

[@cedricstandbridge3144]

Hi! Sorry for the slow response. I hope you were able to solve it. If not, let me know!

[@mortenhjorth-johansen5541]

My NP231 makes a whining noise after I drive 15 min. Goes away after car gets cold. If I remove the front drive shaft I have no noise.

[@cedricstandbridge3144]

Hey Morten! Interesting results... Usually I've found drivetrain noises are worst at cold, so It's interesting yours is noise free at cold. I have some initial thoughts but need more info. Before you took the front driveshaft out... Was the noise a whine or more of a light gear grinding noise? Was there any correlation between your MPH and the severity/tone of the sound? If so, what MPH were worst? Is the sound present when accelerating? Coasting (no gas)? Or present during both?

[@zacharymeredith9093]

I know this was years ago, but I'm responding for others who come across this in the future. The issue is likely the chain. They stretch over time. Cold chain is smaller and tighter. As you drive and warm up the components it's likely expanding/stretching beyond the acceptable "spec" range causing the noise

[@matthewluna727]

Do you think this sound can cause catastrophic failure within the transfer case? I have this same sound..

[@cedricstandbridge3144]

Thanks for commenting, Matthew! In my opinion, I would say probably not catastrophic... without knowing the exact terminology - the ring that serves as a mesh or transition between 2wd and 4wd may start to get worn down its tapered teeth may chip off. This was my situation at least. I solved my situation by putting a thicker gasket between the two transfer case halves to provide some clearance/tolerance.

[@matthewluna727]

@@cedricstandbridge3144 genius!! Thank you for your input!

[@bills4275]

what was the outcome of the diagnosis

[@cedricstandbridge3144]

Sorry Bill for the late response! I ended up making building the gasket between the two cases extra thick to provide a tad more clearance in the case. I did this by giving the liquid permeated gasket maker an extra hour to cure before torquing the bolts to spec. Best of luck!

[@mathewmiller4942]

So what was it ? My dakota making the same noise

[@cedricstandbridge3144]

Sorry Mathew for the late response! I ended up making building the gasket between the two cases extra thick to provide a tad more clearance in the case. I did this by giving the liquid permeated gasket maker an extra hour to cure before torquing the bolts to spec. Best of luck!

[@rickoshea1318]

Did you ever find out the cause?

[@cedricstandbridge3144]

Sorry Jamie for the late response! I ended up making building the gasket between the two cases extra thick to provide a tad more clearance in the case. I did this by giving the liquid permeated gasket maker an extra hour to cure before torquing the bolts to spec. Best of luck!

[@jackskellington7863]

That’s my noise

[@timnostro]

solution?

[@cedricstandbridge3144]

Sorry Timmy for the late response! I ended up making building the gasket between the two cases extra thick to provide a tad more clearance in the case. I did this by giving the liquid permeated gasket maker an extra hour to cure before torquing the bolts to spec. Best of luck!

[@swansoninspections1845]

Your blind bearing at the bottom of the main shaft was not set properly. Mine was too deep. Had to tap it back from the under side that’s resting on the bench.

[@matthewluna727]

I believe I have this same noise, I don’t even know how it came about, I have a 2013 wk2, only thing I can think of is when I swapped the fuel pump out with a friend we had to remove the drive shaft. Can this sound cause a catastrophic failure in the Transfer case?

[@swansoninspections1845]

I believe so. It’s gear teeth hitting other gear teeth.

[@swansoninspections1845]

@@matthewluna727 yes

[@matthewluna727]

@@swansoninspections1845 so where is this blind bearing?? Inside the transfer case ?

[@swansoninspections1845]

@@matthewluna727 pull the main shaft that the shift fork is surrounding. You’ll see it sets in a stamped steel cup with needle bearings around it. I tapped mine down in further with a hammer and a big wood dowel. Yours may need tapping in or maybe it needs pulling out some. But you a figure it out by putting the main shaft back in and spinning it. If it’s quiet, you’re good. If it clunks, it needs to be adjusted accordingly.

[@DooberD33]

I got a clank I can’t tell if it’s my tranny or transfer but I feel it under my feet and that’s where my transfer is

[@jacobunrau179]

Same

[@cedricstandbridge3144]

Hi Doober, sorry for the slow response. I hope you were able to solve it. If not, let me know and I may be able to help!

[@cedricstandbridge3144]

@@jacobunrau179 Hi Jacob. Does does the clank only happen in drive or also in reverse?

[@multipicklefaceful]

@@cedricstandbridge3144 mine happens only in drive

[@joeyfridline8333]

Did you fix it? Or just buy a new one

[@cedricstandbridge3144]

Sorry Joey for the late response! I ended up making building the gasket between the two cases extra thick to provide a tad more clearance in the case. I did this by giving the liquid permeated gasket maker an extra hour to cure before torquing the bolts to spec. Best of luck!