Could my transmission's shims be too thick?

[XC92]

I rebuilt the manual transmission on my '92 Talon TSi AWD a few years ago and it's been working great ever since. But, almost from the start, whenever I release the clutch pedal and the car starts to move, I hear this faint metallic rubbing sound, like when a brake caliper dust shield slightly rubs the rotor. Could this indicate that one or more of the shims I used were a bit too thick?

I used the solder method, multiple times, and used shims that came closest to the average values after throwing out values that were way off. When there was a choice of shim, when the average solder thickness was exactly in-between the two closest shim thicknesses, I believe that I used the thicker one.

If it's not this, any idea what it might be? Throwout bearing issues? Clutch issues? Something else? I'll be taking the trans apart this coming spring, to fix a very minor leak that appears to be coming from the case section seams, so I'll have a look then. Could a slightly too thick shim force the seams apart just enough to cause a slight leak when the car is moving?

Btw I've recently started hearing this very high-pitched sound when moving under 20mph. It's high pitched enough that older people might not hear it since you start to lose that ability as you age. Reminds me of a hearing test sine wave sound. Could that in any way indicate trans issues, specifically one or more shims that are too thick? It goes away after 20-25mph or so.

 

[jdxnc]

If there's too much bearing preload, it would be most noticeable right away. Drain you oil, if it has a metallic sheen, it's usually from bearing wear. I've never heard it make noise though, it would have to be really bad. Throw out bearing is much more likely to cause noise.

 

[XC92]

If there's too much bearing preload, it would be most noticeable right away. Drain you oil, if it has a metallic sheen, it's usually from bearing wear. I've never heard it make noise though, it would have to be really bad. Throw out bearing is much more likely to cause noise.

Car runs fine, no weird smells, I can push it in neutral easily, no weird noises then. I did drain the oil that's only 2 years old recently and it looked somewhat tan/greyish and maybe slightly metallic. There was a small amount of shavings on the plug magnet, nothing major, like a small pea quantity. I only replaced some of the bearings when I rebuilt it. I wonder if that's why this is happening.

What do bad or failing trans bearings tend to sound like? Anything like bad wheel bearings? It's nothing like that. For all I know it's normal and, not having driven my car for 5 or so years until I finally fixed the trans, it always made this sound and I just forgot. And how would a throwout bearing make such an noise? I put in an OEM, with a metal sleeve, and an aftermarket fork, Competition Clutch.

 

[dwb]

So you only hear this when you're moving? What about if you turn the engine off and coast down a hill in neutral and again in gear with the clutch pressed? How about with the wheels in the air and manually rotating each wheel individually?
Have you inspected the transfercase, rear diff, wheel bearings, driveshaft carrier bearing, and halfshaft bearing?

Any chance you can capture it on video?

 

[XC92]

So you only hear this when you're moving? What about if you turn the engine off and coast down a hill in neutral and again in gear with the clutch pressed? How about with the wheels in the air and manually rotating each wheel individually?
Have you inspected the transfercase, rear diff, wheel bearings, driveshaft carrier bearing, and halfshaft bearing?

Any chance you can capture it on video?

I'll do this all in due time, a bit too cold these days so it'll mostly have to wait till spring. I'm just trying to get a sense of the possible causes and if it's something to worry about. It sounds like it's coming from the trans area, though. But for all I know it's something to do with a CV axle, wheel bearing, brakes, etc. I'll give it a thorough go-over when it warms up enough but will have to contend with it till then.

I'll try to record the audio though and post it here. No need for video.