Engine Noise in Drive - transmission Issue??

[SuperCoupe400]

Ever since I picked up my wife's '03 G35 sedan (113k miles at the time) last year, the engine has always made a medium pitched hum when being driven. It increases with speed. For a long time I figured that was just how the G35 engine behaved. Perhaps something to do with how it was engineered. Especially being that there is absolutely no accelorator lag whatsoever - like you normally get from any automatic transmission car.

I know the transmission fluid is due for a change (if not flush). Could the transmission be what is causing this noise? Or do all G35s make this engine humming noise? Mind you, I'm not talking about engine rev. This sound is in addition to engine rev.

Thanks.

[tollboothwilley]

i've never heard this "humming" noise, is this noise constant? Always there?

I have 135k on my car now and I don't have any problems.

[SuperCoupe400]

The noise is constant - whenever there are rpms registering (during movement).

[tollboothwilley]

only under load though? not when you are in park/neutral and rev the engine?

most humming sounds come from a) tires being loud b) tires with little tread left c) driveline

since you say the transmission is responsive and doesnt seem to be slipping I would guess its not related to the transmission.

have you checked the tires? this would be my first guess. It could also be the brand of tires. What brand are you using?

Driveline can sometimes hum when U-joints start to lock up.

[SuperCoupe400]

Nope. Not in park, nuetral or when reving the engine - only under load.

Man, those would have to be some loud tires to make this kind of noise though. They're not winter tires or anything. They're some all-season no-name brand from Discount Tire - Arizonian. That's the brand.

But it's been making that sound since the day we bought the car over a year ago. These tires are only about 6-months old.

The only reason I never questioned the sound in the begining was because I figured that was just what the G35 engine sounded like. But now I'm suspect that it may have something to do with transmission or diff fluid that needs attention.

[joe603]

auto or 6mt?

[SuperCoupe400]

Automatic transmission.

[av8or]

hate to tell you.. but it is probably a bearing in your transmission ( have it verified by a transmission shop ).. that's why you hear that humming noise when the transmission is engaged... i had the same thing happen... good thing i had extended warranty and infiniti replaced my transmission... it'll cost you $5000 for a brand new one... less if you can find a third party to do the repairs... better get it fixed asap... those bearings can come loose and do serious damage... http://forums.g35club.org/zerothread?id=346197

[tollboothwilley]

Ya. You should get it checked out at least to verify if its transmission. If it is, you might save yourself the need for a whole new one and a rebuild would work. If you were savvy with cars and had time you could even do it yourself.

[SuperCoupe400]

Thanks fellas. I'll be getting it checked out asap.

BTW, I am mechanically savvy, but not quite gutsy enough to go ripping apart a trans. An engine block, yeah. But I don't think I want to tinker with a transmission.

[joe603]

Remember that you have a 7-year powertrain warranty...not sure on the mileage cap.

[SuperCoupe400]

Remember that you have a 7-year powertrain warranty...not sure on the mileage cap.

I wasn't aware of that. I'm not the original owner though. If I go to Infiniti (and it turns out to be just a transmission bearing - without any real damage done to other components requiring a complete transmission replacement) they won't try and give me the run-around will they?

[SuperCoupe400]

You know what....Never mind. I just called my dealer, gave him the VIN, and he says my powertrain warranty expired June of this freakin' year!

Sucks to be me!

[SuperCoupe400]

One more question.

If I were to pop the car into neutral (highway) and still hear the noise even after the RPMs have dropped, would that imply that this noise may be from something other than the transmission? Like, perhaps a wheel beering?

[SuperCoupe400]

Good news. Turns out it was a (front left) wheel bearing after all. I've had berings go bad in other cars before, but what threw me off is they never sounded quite like this one.

I'm not able to locate front wheel bearings anywhere at all though, only rear bearings and front hub assemblies (with the bearings in them). Do the front bearings come seperate?

[tollboothwilley]

I think you might have to get it WITH the hub assembly. I don't think they make a seperate bearing for the front wheels.

Hopefully one of the techs will stop by to confirm this.

[tollboothwilley]

Here is the price for the wheel hub & bearing

http://www.infinitipartsonline...gid=0

$147.02 + shipping

doesnt seem that bad to me

you could also call riverside infiniti and check their price

[av8or]

Sucks to be me!

Good news. Turns out it was a (front left) wheel bearing after all.

lucky you... guess it doesn't suck to be you... i'll take the $147 repair anytime...

[SuperCoupe400]

lucky you... guess it doesn't suck to be you... i'll take the $147 repair anytime...

YEAH! Tell me about it!

Guess I jumped to conclusions after reading bad reports about people having similar symptoms and ending up needing $7,000 transmission replacements.
Modified by SuperCoupe400 at 9:00 AM 12/15/2008

[SuperCoupe400]

Here is the price for the wheel hub & bearing

http://www.infinitipartsonline...gid=0

$147.02 + shipping

doesnt seem that bad to me

you could also call riverside infiniti and check their price

Thanks. I couldn't reach that link - some error with the host site. But I actually found them here for $134 (no shipping)

http://www.autopartswarehouse....+7029