Weird sound like a police siren in my C4
03-08-2013, 01:41 PM
#1
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Weird sound like a police siren in my C4
Hey guys,
A 86' Corvette, 114000 miles, manual transmission here.
The facts:
- First, two days ago I was driving on the hwy with the overdrive in 4th gear on, I decelerated a bit to take an exit and switched off the overdrive. For the first time in 2 years I didn't feel the engine brake that one feels when switching off the overdrive, it seems the overdrive kept on even after pressing the button and the light went off. Later on, at lower rpms the overdrive seemed to go away, so it does switch off a while after I press the button.
- Second, yesterday and today I've been noticing a noise somewhere (haven't been able to assess where because it only happens when in motion). The intensity of the noise goes up with speed and looks like a police car siren, and it gets superloud in 3rd or 4rd gear. I think it comes somewhere from the drive train, it doesn't seem to come from the engine but I'm not sure, I'm not able to see it clear from inside the car. Other than that the engine seems to plunge too much when I press the brake in 2nd gear at ~1800rpms, before I used to have some sort of engine brake when braking from high rpms to disengaging the clutch at ~1200rpms. Don't know what the hell is going on but the sound is terrible.
Thanks!
A 86' Corvette, 114000 miles, manual transmission here.
The facts:
- First, two days ago I was driving on the hwy with the overdrive in 4th gear on, I decelerated a bit to take an exit and switched off the overdrive. For the first time in 2 years I didn't feel the engine brake that one feels when switching off the overdrive, it seems the overdrive kept on even after pressing the button and the light went off. Later on, at lower rpms the overdrive seemed to go away, so it does switch off a while after I press the button.
- Second, yesterday and today I've been noticing a noise somewhere (haven't been able to assess where because it only happens when in motion). The intensity of the noise goes up with speed and looks like a police car siren, and it gets superloud in 3rd or 4rd gear. I think it comes somewhere from the drive train, it doesn't seem to come from the engine but I'm not sure, I'm not able to see it clear from inside the car. Other than that the engine seems to plunge too much when I press the brake in 2nd gear at ~1800rpms, before I used to have some sort of engine brake when braking from high rpms to disengaging the clutch at ~1200rpms. Don't know what the hell is going on but the sound is terrible.
Thanks!
03-08-2013, 09:18 PM
#2
Le Mans Master
It could be tranny related, but I think the first thing I would check, would be the wheel bearings.
Jack the tires up off the ground a few inches and grip the tires at 6 & 12 o'clock. If there's much play there, then it needs new hubs. Give them a few rotations to see if there's any grinding noise or anything weird.
Good luck. Let us know what you find.
Jack the tires up off the ground a few inches and grip the tires at 6 & 12 o'clock. If there's much play there, then it needs new hubs. Give them a few rotations to see if there's any grinding noise or anything weird.
Good luck. Let us know what you find.
03-09-2013, 09:34 AM
#3
Race Director
