Input Shaft Bearing Noise? Demons?

TomJK

TomJK

New member
Hey all
I need some help. I'm not much good on transmissions, so of course that's my newest noise...

I've heard the first noise for quite a while (3 years or so), but assumed it was a "normal jeep noise". However, I decided to get to the bottom of it, and do some testing. I put the transfer case in N, to listen to it while not driving. As you can hear, the noise occurs while the clutch is engaged, and disappears while It's disengaged. This lead me to think input shaft bearing. However, while doing this test, I decided to shift through the gears, and that's when I noticed the additional noises while in gear. What could be causing that noise?
The gear noises seem to start in 2nd, and get louder in each higher gear. Reverse gear (not in the video) sounds similar to 5 or 6.
NB - the sounds while in gear are much louder in the video, than in real life. For whatever reason, my phone amplified the sound. In real life, they are clearly noticeable while parked and going through the gears, but while driving they are drowned out by road noise - I'd never heard them until this testing.
I have a 2008 Wrangler JKUX with just over 90k miles. I don't really notice any performance issues, though sometimes there's a hard knock feeling and sound when a new gear engages. Also, I've had an unidentified rattle sound when accelerating, similar to the underspeed rattle sound (though I'm not underspeeding). I'm not sure if that's related, it's been around longer than I remember these sounds, and I've been thinking it's in the rear differential, but who knows.
Maybe I'll try holy water....

https://youtu.be/jegL0ge4F3M
 
I would also say throw out bearing.
Possibly the whining noises you hear in gear is the transfer case being in neutral and the internals spinning. It seems to change pitch with the gears.


Sent from my iPhone using WAYALIFE mobile app
 
Ah yes sorry I skipped over that question, he is correct gears aren’t silent, and the transmission rotating at what would be 40ish mph is going to whine a little as you said you don’t hear that on the road. Reverse should be the loudest as it is a straight cut gear. Guessing the fluid isn’t the newest either in the trans which also changes the noise.


Sent from my iPhone using WAYALIFE mobile app
 
Thanks for the replies, guys!
As for the first noise being a throw out bearing, I thought that kind of sound would occur when the clutch is depressed, but be silent when the clutch is engaged. In my jeep, the sound is happening when the clutch is engaged, and goes away when depressed. I thought that pattern meant an input shaft bearing. Is that wrong?
As for the other sounds, I've now noticed them (just because I know to listen more closely) when driving. However, they're still not any louder.
Yesterday I replaced the factory trans fluid, with Pennzoil syncromesh. So far no difference in anything. I'll change out the factory TCase fluid too, and see if I can figure out if the in-gear sound is coming from there.
 
Snboarder113 said:
If playing with the clutch makes a noise like that or stops a noise like that it’s normally the throwout bearing. How did your fluid look/ smell when you drained it?


Sent from my iPhone using WAYALIFE mobile app
Click to expand...

I see, I really thought a TOB sound would go away with an engaged clutch. Thanks
The fluid didn't seem too bad, especially for 11yo fluid with 99k on it. The plug magnet was pretty loaded, but the rest of the fluid was only lightly glittered. No strong smell. My buddy who does industrial maintenance looked at it, and thought it looked pretty , glitter wise.
 
You must log in or register to reply here.
Top Bottom