richmod

I won't detail the long list of issues I've had with the rear end in myGT since I've done so in several other threads. I'm hoping this post will illicit some opinions that may be helpful in solving the problems I'm having.

Car: 06 GT Auto, 18" BFG KDWS (factory, not after-market)

Current issues:
1) I have a hum-type noise that starts at about 25-30 mph as a woob-woob type sound. Above 30 mph, it becomes more constant (less woob-woob), and not as loud, until you hit 65mph, at which point it gets dramatically louder. After about 70, it's gone,or at least so slight it can't be heard.Occurs in all gears including neutral, even with the engine off in neutral. Occurs in all throttle positions. Same going straight or turning. Road surface has seemingly no effect.
2) Slight gear whine (more of a flutter) on decel 55-40 mph.

Brief (hopefully) history:
Original problem was moan on accel only around 65 mph. Ring & pinion TSB was performed several times, all of which created varying degrees decel whine 55-40 mph. Somewhere in this process I noticed the hum noise. All rear bearings were replaced - no help. Clutch packs replaced - no help. After the last TB attempt, a vibration started at 70 mph. Ford finally said "just put in a whole new rear end". Didn't help vibration or hum, gear whine was actually a bit worse. Vibration was solved finally by replacing the driveshafting (took 3 driveshafts to find one that worked). Ford engineer says the hum is the tires. So I make them put my tires on another Mustang (happened to be a V6). Guess what? no noise. they also put 17" tires from another GT on mine. Guess what? Same noise - no change. So then we go for a ride in another brand new 2007 GT Auto with 18" tires. Guess what - same hum AND has vibration at 75 mph.In addition, I had driven another new 07 GT earlier, and it had worse gear whine than mine, and also had the hum and vibration.

So - what the gell is causing the hum? Possibilties:

1. Tires. if so, than why didn't my tires cause the hum on the other car? And why did my car still hum with different tires on it?
2. Wheel bearing. If so, then why didn't it change when the bearsings and the whole new rear went in?
3. Gears. If so, then why didn't it change with several gear fix attempts as well as a whole new rear end?
4. Driveshaft. If so, then why didn't it change with new driveshaft?
5. Normal noises for a Mustang GT. If so, why didn't I notice it before the repair attempts started?
6. Other - please feel free to post your suggestions.

I'm trying to decide if I should upgrade the gears at an independant shop with hopes that it will also get rid of the hum (I aint letting Ford touch my gears again). But if the hum is something else, I want Ford to fix it. I don't want to lemon law the car since every GT I drove had varying degrees of problems, thus making the chances pretty good that my replacement vehicle would still have issues. I just want to fix the problem, even if I have to pay for it.

So - anyone else have this type of hum noise? Anyone have any other suggestions on what it might be?

moosestang

It would be impossible to guess what it is without hearing it. Are you sure it's coming from the rear? Maybe it's the transmission itself. At any rate I wouldn't recommend replacing the gears, going to a 4.10 ratio is likely to cause more unwanted noise from what i've read.

moosestang

The hum doesn't change with rpm changes?

richmod

Changes volume, but not pitch.

richmod

Definitely the rear. Still there in neutral, soI don't think it's tranny.

If i were going to upgrade, I'd go 3.73.

drbobvs

OMG Rich, you're still having problems?!

I would take it to a performance shop (a good one) and change the rear again with a new ratio. You'd be pressing your luck with 3.73s b/c for some reason alot of us are having noise issues with them as opposed to the 4.10's. Are you an auto? If so even try 3.55's, not that you'll notice a difference but it may help the noise.

If these steps do not help the noise, either:

1)Get a whole new rear axle assembly.
2)Live with it.
3)Sell it
4)Pour gas on it!

Steven6095

I am in the same boat with the rear end.....
Currently working with one of the best performance shops out there and still can't get the rear to shut up.

richmod

Same type of hum sound, or just gear whine?

Steven6095

Actually more gear whine but there is also a hum. A for sure hum from something.

I had a rubbing not a metallic sound but a rubbing sound from my drivetrain somewhere.
Dealer finally found something hitting on the inside of the transmission case. Apparently according to them the cases can be off a few mms.
Not sure exactly what constitues a hum, but it was a noise.

vernstang21

I'm in the same boat. Just bought a 2007 GT Premium 5 spd...at 65-75 mph...it's almost like a rubbing sound/feel....It's driving me nuts. Anyone come up with any more ideas let me know. I'd love to hear your thoughts.