Odd G50 Noise...

[88911coupe]

I did an extensive search and can't seem to find this problem duplicated. I'm hearing a faint but cleat metallic whir or flutter, does not sound like what you would call a "grinding" noise but does sound metallic. I've tried to narrow down the conditions and they are as follows as best as I can tell. BTW, it's not the G50 noise...I know what that sounds after driving 2 G50 cars for going on 12 years.

In gears 1,2,3 four sure but can't tell for sure if in 4/5 b/c noise is faint and may be covered by wind/road noise
Most clear at 2,500 to 3,000 RPMs, seems to disappear above 3k
Will go away if I take it out of gear
Hear it whether accelerating or decellerating or steady speed, so long as in gear
If driving next to a wall on drivers side hear it more clearly and really sounds like soft metal just barely touching something. Sort of a "hollow" whirring? sound, not really grinding

Thats about all I can say. It seems to have begun in the last 2-3 months or so.
Car has 180k, no tranny work but Mobil 1 tranny fluid changed in last 6 months or so. I purchased the limiited slip version and was told it would be ok for my car even though it does not have LSD.
Any ideas or questions?
TIA

[88911coupe]

Superbowl Sunday bump...any ideas?
TIA

[jorian]

Does it go away with the car in gear AND the clutch all the way in?

[timmy2]

CV joints in good shape with enough grease? Loaded in gear they are noisy, unloaded no noise is common.

[88911coupe]

Jorian, if I depress the clutch pedal it seems to nearly completely go away. CV joints have been greased but they are original...I think. The noise does not seem to vary whether I'm accelerating, coasting, or decellerating...so long as the car is in gear. It's pretty baffling.

[Deadeye]

Buck, for about $22.00 you can send an oil sample from the gearbox to a lab such as Blackstone for analysis. They will be able to tell you if you have too much metal in the fluid. The magnetic fill plug is also a good indicator.

[timmy2]

Assuming you can't hear that noise unless the car is moving,(to rule out engine mechanical)
Think about the difference between loaded mechanical actions versus unloaded for the noise(s) you hear.
Release bearing starting to fail? Clutch and or pressure plate wear? Motor/tranny mounts shot?
Drop the fluid, inspect the drain plug and send out a sample for testing as suggested if you can't find a mechanical cause.

[88911coupe]

OK...decided to dig into this on a gorgeous saturday here in Dallas. Sound still occuring but no better/worse but bugging the heck out of me. I have the car on jacks and then started to car and put it in gear...no noise at ALL that I can tell. I have noticed the drivers side drive shaft is leaking grease badly on the "inside" end near the tranny. Maybe really low on grease....
I suppose it could still be the tranny, but only occurs when under loan but not really sure how to tell.

[steely]

Originally Posted by 88911coupe

Jorian, if I depress the clutch pedal it seems to nearly completely go away......

Originally Posted by timmy2

...... Release bearing starting to fail? ....

Sounds like a likely candidate and mine does the same thing &is over 110k miles.
Beautiful time of year to work on her (around these parts anyway).

Buck - Please let us know what you find out(?) and thanks for re-posting.

[88911coupe]

Just to clarify...I have been able to determine that the sound does not go away when depress the clutch. Part of the problem is the sound is not really that loud, it's sort of a slight faintly metallic whirring. Seems more noticeable at lower gears but I think wind and road noise are just drowning it out. On a side note, had to listen to my wife's A&M Aggies beat the hell out of my Mustangs while working on the car. Oh well, at least it's not 105 anymore!!!

[88911coupe]

Just in case anyone is interested I think I've solved the problem (fingers crossed). I took both rear wheels off the car and was looking around to see if anything looked loose that might be causing the faint metallic noise. I got distracted by grease coming out of a CV boot and veered off into a driveshaft removel project which required removing the support "bracket" on the driver's side which got me thinking...maybe that had something to do with the noise. I discovered the tab going to the cat/cover apparatus had broken so I took the whole thing off and finished up the project. I decided to leave the support bracket off and drive the car...the sound's gone now. I am guessing that the cracked end of the bracket was causing some sort of rattle to resonate in the cat heat cover.

[Dublinoh]

Originally Posted by timmy2

CV joints in good shape with enough grease? Loaded in gear they are noisy, unloaded no noise is common.

Did you grease the CV joint? I have a similar metallic noise, like a band saw cutting metal but not loud at all, faint; and only under load 4th gear mostly. I am thinking this might be CV joint from the quoted post...and you found leaking grease...just curious

[88911coupe]

I did not add any but could feel that it was still pretty full of grease and very smooth in operation. I could not feel any rought spots or binding at all. I did purchase some new grease afterwards and probably will find a way to get some more in there. I was wondering of there was some sort of way to "inject" it through the small end on the shaft.

[Dublinoh]

88911coupe appreciate your reply...

[BHP231]

Going back to some earlier posts on this thread, I have a whirring sort of noise I can hear when at idle, it completely stops when I depress the clutch. It seems to be more obvious once the car is all warmed up.
My local specialist isn't sure what it is but thinks it could be the needle thrust bearing...?
It doesn't mean much to me to be honest but if anyone has anything they can add it would be appreciated.