GarrettJ

Alright guys I originally thought my howling, whooo noise was the transefer case..well I rebuilt it and got it back on and my yeep is still making the same noise..ive got a 2001 sport 4x4 auto 4L stock..ive been looking up videos for the past couple days and im back on the same ones now..only howls, whoo while accelerating..as soon as I let off the gas it stops and the second I hit the gas it starts again and pitch seems to fluctuate with speed...comes on at about 20-30mph and seems to go away or so faint I cant hear it at about 65mph


ive got the rear diff cover off, both wheels, drum covers and drive shaft off the rear..I checked for any kind of play I could and the only thing I can find is a tiny little bit slack in the pinion just rotating it, to my knowledge this is normal..ive checked for wheel bearing movement before I took the tires off and no movement what so ever, just very very very minor in and out movement, which during my search seems to be normal..the drive shave ujoint, although beat up, seems good but i've already got a new one to replace it..


the front wheels, ive checked for wheel bearing movement and cant seem to get any there..checked my ujoints and my front passenger has enough play to warrant changing it out, but im not convinced that it is making the noise.. ive disconnected my front drive shaft from transfer case and tried finding play in front pinion and found none..i just changed that fluid out a few days ago and everything seemed alright..wheels and tires are still on though..should I go ahead and take the tires off and remove front diff cover and try investigating something further? ?


Im lost and this noise is killin me.. im not buying a lift kit, wheels, and tires until I can get rid of this noise!



You can hear me getting on and off the gas

zr2toxj

It sounds like gears to me. As in R&P gears. I would pull the front DS and drive it and see if it is still there. You could also put the front DS back in and pull the rear DS and run it in 4wd to see if it changes. While you have the dif covers off, run your finger on the outer edges of the gears and see if they are sharp. I would also do a pattern test on the gears you suspect to see the runout. That's pretty easy to do just to see if there's a problem. Could be a carrier or pinion bearing that is bad and making it howl. Good luck! let us know what you find.

ZJMAX

My guess would be bad carrier bearings letting the carrier walk just a hair. This lets the ring gear move away from the pinion just a bit so the gears run out of spec.

Max

Turbo X_J

Does either pinion seal leak like a sieve? I'll vote rear pinion bearing. Grab the companion flange and see if it moves side to side or up and down.

Roler

Sounds like mine, when 4WD has not disengaged.
Your fluids all good too, like trans/transfer/diffs?

GarrettJ

Thanks for the responses guys! Ive got no up and down or side to side movement on either pinions! Have not had a chance to pull drive shafts off and test drive, need to pick up more gear oil today so I can try that. Ive only checked the rear gears and I don't feel any sharp edges on any of the gears. I cant get any movement on ring gear bearings. And there is evidence of an old leak on the bottom of front diff but I just drained and filled it the other day and it was full, which means before I got it.


Here though is a weird sound I found just trying to find something unusual. Sorry for the lawnmower but I couldn't wait to make this video, have some errands to run but thought important to get yall a couple vids since yall thought it worth it to respond to me..


Sand noise?


Then no sooner than I turn off my camera and turn it a couple more times the sand noise just went away? ? ? Also, got a shot of the rotational movement that I am lead to believe it normal? Cant get and axis movements out of pinion..again, sorry for lawnmower






Let me know if you guys think im getting somewhere..i mean i got the tiniest axis movement out of rear wheel bearings but only achieved after removing drums..thanks for any help!
EDIT: You guys don't think it could be the Double Cardan making that noise? Don't think so myself but i throwing out anything that has rotational movement

Turbo X_J

Probably not sand, just and bad bearing /race (that's your "howl"). Time to think about tearing it apart or take it to a gear shop. If you want to change the gear ratios now would be a great time.

Kalali

Your Jeep sounds like a lawnmower...

GarrettJ

You think that little bit of grinding could be the entire problem/howling sound? Even with zero movement in the carrier bearings?

zr2toxj

It's not hard to pull the dif and with that noise, I would be suspicious enough to want to find out more. Is that in the rear or the front dif? Either one isn't that hard to pull the axles, mark the bearing caps and pop the dif out, then you can see if there is any wear on the bearing races or play in the pinion bearing.

GarrettJ

Alright with the limited time i had i was able to pull the axels out and take off "bearing clamps?"..that was all the time i had yesterday and now I'm at work today so i wont be home for 2 weeks..but when i took off the 4 bolts for the carrier bearing clamps and couldn't help but notice a very strong all most sickening smell on the bolts that traveled upstairs and wouldnt go away for a while..cant describe exactly but it was one of the strongest smells I've ever smelt and had us gaging for a bit haha..anyone every smell that before while taking off diff gears?

Oh and i couldnt get the gears out but i didnt try very hard..needed a pry bar which i didnt have and like i said, ran out of time..ill be able to check the bearings once i get back home

Chuber

I am in the same boat. Noise is identical to the videos. Chrysler 8.25" on a 2001 XJ Sport. I've read another thread here of someone experiencing the howl, swapping out the rear end (a Ford 8.8 from a Chryco 8.25) and still hearing it. However, the grinding noise in the video sure does sound like a worn bearing. I assume there were no rollers hanging around in the bottom of the case, but were there any shavings and/or was the fluid in bad shape? That terrible smell could very well be cooked lubricant.

I'll pull driveshafts and troubleshoot front vs. rear, but have you gotten any further with this? All signs point to pinion bearing, but I'd like to rule out all options before taking action on the rear end.

With that, if the pinion bearing goes bad on a Chrysler 8.25, is the best course of action to: a) replace with junkyard post-97 Chrysler 8.25 or b) rebuild with rowdy awesome new gears even if I don't want to cross the Rubicon? What is reasonable for option b at a decent rear end shop?

--Clay