I've been noticing these for a while now and just had the time to try and pinpoint it now. I'm going to try and post a link to the video soon but the first noise is a knocking sound, and it sounds like it's coming from the transmission. I've never heard a transmission knock before, so any help is appreciated. When I checked the fluids, everything seemed good so I'm not sure what's going on. From what I've heard, it's only happening while idling. It's a steady knock that goes away when driving.
The second noise is what can best be described as a screeching I think. It was happening only in the mornings after the Jeep sat overnight, and does it while idling and then while driving for the first 30 seconds or so (usually gone by the time I hit 3rd). Lately, however, it's been doing it after the Jeep sits for shorter periods of time and the noise is happening for around the first minute I'm driving. Trying to describe it, it sounds like a metallic screeching noise that does it when idling, while revving, and while accelerating. It sounds like its coming from under the jeep, just forward of the gear shift, but I'm not 100% sure on that.
Any help with these is greatly appreciated! I had two mechanics take a look over it in general when I bought it a month ago and they only found that it needed a new belt and the front axle has a very small leak. Both said that could wait a while. Of course, neither of these noises presented themselves with the mechanics. Thanks!
I listened to the knocking again this morning and it still seems like it's coming from the transmission or just above it maybe. Again, any advice is appreciated!
manual transmission? If so, does the knock occur when you have the clutch depressed? If it goes away when you touch the clutch pedal it's the Throw out bearing rattling.
On the screech, this could also be the Throw out bearing...or the pilot bearing. It will seize up if this is it.
Mrcar, thanks for the reply! Yes, it is a manual. 6 speed. I got in my jeep to go home for lunch today and it didn't do it on the way home. Once I parked, I put it in neutral and let it idle, still nothing. I gave it a little gas and right when I pressed the gas, I could hear the knock, but faster than normal until it revved up a little and stopped, or the engine noise overcame it. When I let off the gas, the steady knock was back. When I pushed the clutch in, the knock went away, let the clutch back out and it started back. I did this a few times to see if it was constant and it was. Little gas = fast knock, idle = steady knock, clutch pedal pressed down = no knock. Would this be the throw out bearing?
Most likely yes. I'd classify it as a rattle. But it's a very distinct noise no matter what you call it. To further test, get the knock going then rest your foot on the clutch (light pressure, not enough to do anything to the clutch.) see if the noise stops if it does then it's the Throwout bearing. It's not necessarily a sign of anything bad...I remember mine did that before the T.O. Bearing decided to grenade one day, I can't remember if the replacement did it....been too many hours of sleep since then.
That squealing would make me more nervous. (if it's what I think it is.) If it's the pilot bearing I'm sorry.
just save up enough for a clutch replacement (I strongly suggest having the flywheel machined at least when replacing the clutch.) Ironically my flywheel looked fine and had no hot spots, so I roughed it up with a scotchbrite or something and put it back together. On my higher HP cars I always machine or replace the Flywheel when I do a clutch.
The Jeep kinda sucks to do a clutch on...especially if you're an idiot like me and decide to keep the Tcase and Trans. together when you remove em. That's a tough bench press to do (I'm a girly little dude)...I ended up using my legs and arms to lift it off my chest (Did I mention I'm an idiot?). and stabbed it back in place.
If the clutch/transmission noise goes away when the clutch is depressed, but noticeable with the pedal up, then it is not a throw out bearing and most likely not a pilot bearing as neither are spinning with the clutch pedal up (although a really bad pilot bearing may cause an alignment issue which could cause noise). The noise is most likely the input bearing on the transmission (if it is also happening sitting in the driveway in neutral).
I agree with brerndend, that you should check the opda for the screeching.
Thanks for the opda suggestion. I checked out some of those videos and I'm pretty sure that's it. It's coming from that area in the engine bay, and I thought before it be bearings in something but after taking the belt off to replace it and everything seeming fine I was ruling that out. I'm doing a little more research on the opda but it seems that's the culprit. Thanks!
Y'all hit the nail on the head with the OPDA. I replaced it this past weekend and no more squealing. Thanks!
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