Engine/transmission high pitch whine
 

Hey,

I need some assistance diagnosing what is wrong. My engine bay or transmission has this high pitch whine since Tuesday (couple days ago) never had this for 68k until now. It seems to be most audible after a cold start and under load. At first I thought it was my transmission but now I'm not sure as I heard it a little when in neutral. At first it was just when the engine was cold and after heating up the sound would go away. Now the sound is not going away after it is fully warmed up. I haven't noticed any other issues besides the sound which is clearly abnormal. I did replace my battery about 3 months ago. My car is completely stock except for a catback exhaust and had all its required maintenance done on time.

I did post in another older thread but I now don't think this is the same issue. My car sounds just like in this video
Video example: [ame="https://www.youtube.com/watch?v=LOJAnWEanmk"]FRS - High Pitch Whine - YouTube[/ame]

It seems like this has happened to others and if this is already adressed in another thread I apologize. In the comments it is mentioned this is due to a bad alternator diode, not sure if that is the actual cause. If any more experienced members can give me any advice it would be greatly appreciated.

I thought I'd add my own video I took of the sound. It seems to get more loud when I press in the clutch but still can be heard in neutral.
[ame]https://m.youtube.com/watch?v=d7S0kV51IGM[/ame]

hmmmm........if your car's transmission is a MT, it could be the throw out bearing is getting tired .....:iono:

Hey @Ultramaroon ....... do you hear any gear rollover .....??


humfrz

Yeah, I responded to your earlier thread on this. Get an inexpensive mechanic's stethoscope. Or if you have short hair, a screwdriver will do. Touch the alternator while it's running and lay your ear on the handle. I bet you'll hear that whine coming from it.

The other thing you can do to test is disconnect the accessory belt. Don't have to completely remove it so it takes only a couple minutes. Just make sure it's not hanging near the crankshaft. Start the engine and quickly listen for the sound. Do not run it any longer than, I dunno, 15-30 seconds because the water pump is not running.

If you still hear the sound, which I seriously doubt, you'll be in for a real treat because, unless you failed to tell us about having a blower, the only other thing that could potentially make that sound is the oil pump.

Thanks for the advice, I actually bought an automotive stethoscope yesterday and I tried for a few mins listening with it touching the alternator and didn't hear the sound. It isn't constant and seems to go away after the car warms up which made me wonder if it is the tob. ( I didn't spend enough time listening to the alternator to rule it out however) This weekend I will have more time to hopefully diagnose where this inconsistent sound comes from. I did come across this post which also describes what I'm experiencing

So @ultrmoon you don't think this is a tob issue and likely something else causing the sound?

If it was, you would hear it change as you tapped or jiggled the clutch pedal.

One more thing that just popped into my head. Really an outside possibility but if something was rubbing on the ring gear on the flywheel, it could make that sound. Do you still have that rubber cover installed over the top of that service hole on the top right side of the block in the back? Sometimes that thing melts and makes a mess inside the bell housing.

Thinking about it, more likely than the oil pump. Just pulling ideas out of my ass here.

Oh, and if it is the alternator, it would make sense that it goes away after driving for a bit. The alternator is doing most of its work to recharge the battery after it started the engine. You could try firing up all the lights and crank your cabin fan up high. That'll put a load on the alternator too.

Thanks for the ideas I will try and check the oil pump and flywheel. I think it may be the tob when I start the car I don't really hear it until I press in the clutch pedal. While pressed the sound gets loud and then I hear it slightly during idle. It also changes with rpm when in gear but in netural it doesn't seem to change much or is much more quiet. In my video you hear it get loud when I put it in reverse and start backing up and going in gear. I will investigate this weekend and report back with what I find. I appreciate the tips.

My pleasure. Let us know what you find. I'm curious as hell. :popcorn:

edit: I went back and listened one... more... time. I clearly hear the whine and honestly don't get TOB from it. :iono:

Ring gear is loose or it's off it can happen in these cars fairly
Regularly. . . Find out the ring gear size(very hard to figure out)
Heat up the old one if you're not switching everything for a grand or 2.
And throw the new one on the flywheel(if there's no damage to flywheel)
You'll need a torch etc

I cant hear anything wrong in these videos, am I supposed to be hearing anything? Sounds really normal to me.

Quick update. So I used my stethoscope and listened all over. I have determined it is coming from the transmission. So I decided to take it to my mechanic (I'm not as handy as I'd like to be) for a pro to check it out. He thinks it is likely the tob. It is certainly coming from the transmission housing and mainly manifests when in gear or clutch is in and the engine is cold, it also totally goes away after its warmed up. I'm going to get my tob replaced and a new clutch kit while I'm at it. I hope it's not the ring gear but my mechanic (@theracersline) will hopefully be able to figure it out.

I appreciate all the input and will pass it along when I see my mechanic. I'll also update in the future with what the cause actually was and what the fix ended up being.

So thought I'd share the solution. It turned out to be the throw out bearing. I got it fixed the other day and my bearing was shot and noisy when it came out. I also had a new clutch kit installed and the whine now is totally gone.

Wow! Never in a million years would I have gone along with TOB.


Thanks for following up here. Your recording is really good so this is one for the books. Glad you got it!

Just curious, how much was it to replace the throwout bearing?