So on Monday, I traded in my 2012 v6 for a 2012 gt. It's got about 8000 miles on it, at a local ford dealler. and seemed like a sweet deal. Took it for a test drive everything seemed good. Heard a slight squeak when pulling out of the dealer parking lot and mentioned it. The salesman said oh must be the tires on our new asphalt. Ok. So I buy the car a few days later. No problems drove 5 miles home and back to the dealer in the new car. And the rear started groaning and whining by the time I got back. What the heck???????

So the dealer took a look and blamed it on sway bars and exhaust. Fixed the sound or so they thought. Drove home and it started doing it again as soon as the car got warmed up. It only happens at slower speeds and while turning. No noise going straight.

Went back to the dealer and told them it is still there, so the mechanic asked me to drive it for a couple days and bring it back if it was still making the noise. The salesman called and let me know they want to get it right and sorted out. But I'm getting the feeling they are avoiding getting it in the air by a certified rear end specialist . It seems obvious to me that it must be the clutch plates in the rear end or an improperly installed rear gear.

Please help!!! I'm not sure what to do. I feel that the dealership should take responsibility but I really don't want this to be a drawn out process back and fourth until I end up paying for the repair.

 

Is it a track pack GT or no?

Either way, most limited slip diffs will make noise while turning at low speeds. This is especially true of the standard limited slip, which uses clutches. The friction between the clutch discs must be overcome for the two rear wheels to move at different speeds, and that will make noise.

 

Base gt, but I'm not sure whether the rear end is all oem or not

 

All Mustangs from I think 2010 up (maybe 2011) have a limited slip diff. The specific diff you have will depend on the options of the car. It's fairly unlikely that it's been swapped all things considered, especially if the rest of the car is stock.

If it only makes noise at low speeds while turning, that is very likely the cause, and it's very unlikely that you'll eliminate it. It's just how they operate. If it's something different then it could be a cause for concern.

 

Maybe change the fluid to full synthetic or add a friction modifier. Maybe someone changed the fluid in it and didn't use the modifier or synthetic fluid. You have to use one or the other and that would cause the clutches to chatter and bind.

 

My 2014 Base GT 373 rear end doesn't make any low speed noise, turning or not. I have had other cars with posi-traction that growl when turning slowly. I do have a slight rear end hum / noise at highway speeds but not bothersome enough to have the dealer start messing with it.

 

I took this video to show the dealer, but it definitely the lsd right?

 

Just picked my car up from the dealer, took it in for a rear end clunk when going over bumps. They said the noise was from a loose pan hard bar. Noise is gone now thank god.

 

It's just such a bummer... So excited about getting into a new car and then noises....

 

I feel your pain, bought my car about 4 months ago! The noise got so embarrassing to where my girl friend even pointed it out. You could always get a louder exhaust to cancel out some of the noises lol jk. I hope you get it figured out!

 

To be honest it sounds to me your wheel is rubbing. It does not sound metallic, it sounds as if your wheel is scraping something. Now do this at your own risk, or get a friend mechanic to help you out.

Go ahead and lift your car ( rear end ) on two jack stands. Put the car in gear and do not accelerate and look / hear what could be going on. AGAIN JACK STANDS not just a JACK!

Edit: Update i just saw you are doing a circle.. It could be the diff.... Can you feel the issue inside the car? A blown rear end, seal, bearing, carrier bearings, LSD will deff have issues.

A LSD issue with cause gears to chatter... CLICK CLICK CLICK CLICK CLICK CLICK, A PINION GEAR ISSUE SOUNDS as a WHINE and hmm.. Almost feels like rubber is rubbing...

 

It sounds like this ^ to me. I heard it before on other cars; and, it will get worse the longer you drive it. Add a little friction modifier and see what happens.

 

yea, I agree. I've never had any personal experience with rear end chatter, but all the research I've done points to that. Now the trick is getting the dealer to get someone to take a look at it. I'm planning on bringing it back in tonight to have them flush the oil and re lube, adding in the friction modifier. It'd be awesome if they popped the cover off to look around while they are at it. :/

 

I had a similar sound in my 2000 GT after a rear end bearing debacle that was a nightmare. Anyway after I drove the car for a bit I'd get this weird creaking groaning sound and it happened quite a bit when I was turning. It ended up being the clutch pack.

 

if you don't mind me asking how did you have service the clutch pack? Was it the dealer? and if you can remember how much did it run you? I'm worried I'm going to have to pay out for this in the end...

 

No one could give me a clear answer until I took it to the dealer. Like you I wanted the whole differential opened up for a looksee. I don't remember the costs but it was in the hundreds. I know that doesn’t help but I do remember thinking it was a reasonable amount of money and not outrageous. Hope this helps.


The more I watch your video the more it sounds exactly like my issue.

 

If it is only when turning left and right, I would bet it's the LSD clutches. Drain and refill with Synthetic Lube and Ford Friction Modifier. Worse case have them put new clutches in the diff. It's not a hard procedure as I have rebuilt 100's of 8.8's.

I am very disappointed in Ford rear axles as of late. I have owned so many Ford vehicles with 8.8's over the years from Mustangs, Explorers etc... I own an independent auto repair shop and have setup may rear end gears.

I feel like when Ford switched gear ratios (and possibly suppliers) from 3.08, 3.27 ratios to the newer 3.15, 3.31 they became much more problematic. I know when Ford Racing switched suppliers of their 3.73, 4.10's for a while had many noise issues.

My 2014 GT started making decell gear noise from 50-35ish mph with only 900 miles. I now have 2000 miles and is about the same.

I fear bringing it in to Ford as I feel like it's few and far between to have a skilled/dedicated driveline tech at these modern dealers.

I mine continues, I may check the backlash numbers and read the pattern with some marking compound and adjust. If that doesn't do it, I'll swap my 3.15 gears for some 3.27's of the old variety.

I'm just a bit pissed, as this is my first new car and as a mechanic, I bought this thing new so I wouldn't have to be working on it...as they say, if you want something done right, you got to do it yourself!

 

That sounds awful!
Something isn't right. I agree it sounds like a tire on the video but I wouldn't drive it 1 more mile until they figure it out.


Or... look for another GT.

 

Your tire is definitely rubbing on something. I say avoid yourself a headache with the deale and stick your head under there and poke around.

 

that sound is horrendous!! its definitely not normal