Does anyone else, notice a bit of a hum once they reach around 70mph to 75mph. Maybe its just because the car is so quiet, but it does bug me.

 

Turn the radio up...

 

I've heard of this a couple other times and if I remember correctly it was an issue with the axle of something in the steering and I believe it became more defined with the sport mode on? Don't remember exactly, is it coming from the wheels, engine, tranny?

 

Tried switching between comfor standard and sport, no difference. Sound seems to be from the front, not a growl like a bearing just a hum, I'm still thinking bearings. I am goin to the dealer this week to test drive another one

 

Dealer is your best bet

 

I wanted to make sure it wasn't just a characteristic of the car

 

Could be the road noise

 

Can't say I drive between 70-75 that often, haven't noticed anything at higher speeds though.

 

Steve, only done 230kms on my car, haven't hit the hwy way yet, not done that speed yet. Have you gone passed 1,600 Kms already ? Could that have anything to do with it perhaps ? Still too new ?

 

Doesnt sound like road noise, only has 400 km on it, maybe It'll go away. When I test drive another one I'll know

 

Hum/Growl/Buzz comes gets very noticeable at 140 KPH, and can hear it buzz down until around 80 ish, then it dies out... Drives me nuts

 

I notice a hum when I'm driving at under 1,500 rpm and it kicks up to the next gear (auto) it sounds like a drone type of hum, is that what you are referring too?

 

Is the noise there if you pop it in neutral? What rear gearing do you have? I've got 3:73s and was getting a similar noise between 65-75 mph and it also sounds like it is coming from the front. My noise is like a low rumble/growl/rough sound that was heard but not felt (kind of like a muffler drone though not quite as loud as that). Dealer diagnosed it as a drive line drone and replaced my drive shaft. That helped but did not eliminate it completely. I drove another new GT with the same gearing and noticed it around 70 mph.

There are a lot of issues with the 2 piece drive shafts on these cars. The fact that the center support bearing is bolted directly to the under body sheet metal doesn't help as any drive line harmonics are transmitted directly into the cabin. And with the higher numerical ratios gearing the shafts are spinning faster so a guy with a 3:31 axle may not really notice anything unless he is driving 85 mph which may be an infrequent occurance.

Seems like a lot of guys dump them and go with the aluminum one-piece shafts and have reported less noise, vibration, and better acceleration. That may be an option for me in the future.

 

Mine is at 460km I haven't noticed this ill try to simulate it again

 

It's speed related not engine related, I think it may be the driveshaft, it's mt with 3.73. See if the dealer will put a new shaft in it

 

Let us know how it goes. The new shaft help mine but did not eliminate it completely. I may try re indexing it. There are six opportunities to re index and some folks have been known to put a washer or two under one of the six bolts, but all of that takes a lot of time to re index, test, re index, test, etc. and the dealer is not going to want to invest a lot of time in that.

If you get an opportunity to test drive another, make sure it has the 3:73's in it.

 

Any updates on your issue?

 

Been so busy, at the dealership multiple times but never had a chance, or energy to take one out.

 

my '10 was bad @ 70mph then went away above 80, pretty sure it's the driveshaft. '13 is a little better but still not great