Low whining sound from undercarriage

[ZR11974]

Good morning to all. I hope this email finds everyone well.
I am a new ZR-1 owner and am hoping I can draw on the vast knowledge, here.
The car is a white 1990. It only has 30K on it and is in excellent condition. I love the car. Lifelong goal achieved by getting the legendary LT5 underfoot.
However, I am experiencing a low whining/whirring type sound from under the car. It does not seem to be changing the cars performance. It's just a concerning sound, and it's loud.
It does not appear to be exhaust.
It is not throwing any warnings, and none of the battery, oil pressure/temp, or normal temp gauges are effected by it. Neither is the idle. It sounds like it might be a belt. But, it starts and ends while moving or sitting still, and it never continues once I accelerate. And, as best as I can tell it appears to be coming from the front/center of the car, not the rear.
Steering also doesn't seem to be related.
I keep trying to isolate some consistency with it, but no luck so far.
And, as I've said, it is loud. Almost like a smaller engine is revving, but not the LT5.
Since it comes and goes with clutch release and depression...sometimes...clutch is my gut feeling.
Any troubleshooting suggestions? I have considered buying a code reader, or using a paperclip trick I read about to see what is stored on the ECM.
I absolutely adore the car, and this weird *** sound is the only thing I'm concerned about.
Thanks for taking the time to read all this, and I hope the day treats you all well.

Respectfully,
Geoff

[Paul Workman]

The 90s have straight cut gears in the ZF which produces some gear whine, especially in 1st and 2nd, I find (in my 90 as well). AND, it comes when the clutch is out and goes away when the clutch pedal is engaged. But, if you noise is the opposite, then throw out bearing comes to mind - except seems unlikely with so few miles.

There are many members in your area that might be able to drop by your location and assess the sound with a learned ear. Aside from that, have you changed the transmission fluid yet? Changing the trans and differential fluid - may or may not improve the sound (if coming from the trans), but then you can check that off the list and you'll know that isn't the issue.

Perhaps Mark Horner or one of several other local Texicans can give it a listen. And, given that gear whine is the nature of the beast in the 90 to mid 92s, if that is all it is, the fix is turning up the radio or installing headers w/o cats! (kidding ya!)

[Dynomite]

Originally Posted by ZR11974

Good morning to all. I hope this email finds everyone well.
I am a new ZR-1 owner and am hoping I can draw on the vast knowledge, here.
The car is a white 1990. It only has 30K on it and is in excellent condition. I love the car. Lifelong goal achieved by getting the legendary LT5 underfoot.
However, I am experiencing a low whining/whirring type sound from under the car. It does not seem to be changing the cars performance. It's just a concerning sound, and it's loud.
It does not appear to be exhaust.
It is not throwing any warnings, and none of the battery, oil pressure/temp, or normal temp gauges are effected by it. Neither is the idle. It sounds like it might be a belt. But, it starts and ends while moving or sitting still, and it never continues once I accelerate. And, as best as I can tell it appears to be coming from the front/center of the car, not the rear.
Steering also doesn't seem to be related.
I keep trying to isolate some consistency with it, but no luck so far.
And, as I've said, it is loud. Almost like a smaller engine is revving, but not the LT5.
Since it comes and goes with clutch release and depression...sometimes...clutch is my gut feeling.
Any troubleshooting suggestions? I have considered buying a code reader, or using a paperclip trick I read about to see what is stored on the ECM.
I absolutely adore the car, and this weird *** sound is the only thing I'm concerned about.
Thanks for taking the time to read all this, and I hope the day treats you all well.

Respectfully,
Geoff

Difficult to understand exactly when you hear this "smaller engine revving".

Seems most likely Serpentine Belt or tensioner but then you associate Clutch operation which is confusing

We have the AC, Water Pump, and Power Steering as well as Alternator rotated by Serpentine Belt Also.

[ZR11974]

We can all rest assured I am confused, as well. Haha.
I have not changed the fluids, yet, but considered that. And, I am almost certain it's not the well-documented ZF gear whine. I think I hear that, and I actually love it. Haha.
I'll check out the Serpentine belt, visually and see if anything looks amiss.
And, I'll see about reaching out to some of the Texan locals!
Thank you very much for the ideas, and suggestions.

Geoff

[Mystic ZR-1]

Pilot bushing?

[ZR11974]

Mystic ZR-1,

Certainly could be, but I have no experience with that as an issue. I'll have to look into it. Any ideas on how to identify that as a possible culprit?
Thank you very much.
I'll definitely be doing some research, this weekend!
And, here's a pic of the car:

[DRM500RUBYZR-1]

Originally Posted by Mystic ZR-1

Pilot bushing?

Great minds think alike hah hah.

How loud is loud?
Is it always there or does it come and go.
Is it loud enough that when it starts, does it get the attention of the car next to you?
Is it a "howling" noise.
30k miles is about the mileage my first ZR-1 had when the pilot bushing went.
It spins around in the crank and can make a variable pitch, variable volume noise that starts on its own and can disappear at times. (at least in the beginning)
My car would scare adults at the corner when it would decide to howl.
Marty

[Mystic ZR-1]

Originally Posted by DRM500RUBYZR-1

Great minds think alike hah
Marty

Scary...

[ZR11974]

DRMRUBY500ZR-1,

I think we may have a winner...it's loud enough to scare the dead. And, loud enough I always try to make it stop, because it makes my beauty sound like a beater!
Definitely comes and goes.
And, it could be described as a howling...not to be confused with the werewolves. This is louder. Haha.
I'm definitely going to do some researching as I think you've nailed it.
Did you do the job yourself, or have someone do it.
The ZF has to come out to get to it, correct?

[ZR11974]

That last question was a dumb one. Let me go with, is it as involved as I imagine to repair?