Running noise

[carmine34]

Hello, thanks for letting me join! I'm new to the modern Mustang scene and just bought a 2008 V6 auto which is pretty much stock except for the PO must have changed the rear end to a posi and possible lower gear ratio. So I'm having this nasty howling/moaning at all speeds but worst over 40mph. Bearings and brakes check out ok. I think the tranny is fine but I can't tell if it's the rear end or the tail of the tranny making all the noise. Also the tranny shifts thru all 5 gears before 40mph. Seems like the speedo is 5-10mph over what it should be. So if it is the rear will the Ford friction modifier help clear up the howling? Also, is their a way to tune the shift points so it shifts later? I did the half ass drain the tranny of 3 quarts and dilute it a little with new Merc 5, the fluid is dark but clean, she has 56k on her. Driveshaft is still original 2 piece but seems to be solid no flex. Help any suggestions for getting rid of this moaning is much appreciated!

 

[VistaBlue09]

Does the car do a one wheel or two wheel burnout?
Can you contact the previous owner to ask what was done to the rear axle? Is it a stock 7.5 with a Traction-Lok added with lower gears? Or an 8.8 from a GT?
If the gears weren’t done correctly they can be very noisy whether it’s a 7.5 or 8.8 rear axle.

 

[carmine34]

Unfortunately, no I can't contact PO, yes it's definitely posi now, so the V6s come with an open 7.5? I thought they were all 8.8? The axle code is: BG open rear. I had it up on jacks and confirmed its a posi so the guy had it changed. Sounds like this is not the rear end I would want to learn how to change gears and set lash on? Sounds like someone with a lot of experience needs to work on these? Is there a chance the friction modifier would quiet it up any?

 

[JimC]

All 2005-2010 V6 Mustangs came with the 7.5" open diff rear end. It was common to swap to the 8.8" rear end with tlok because the 7.5" was easy to break. One of the problems that people had making the swap was the crush sleeve and pinion not being set properly. The 8.8 rear end requires the Ford friction modifier while the 7.5 didn't need it with the open diff. If it is already "singing" then the damage is done and adding modifier likely won't quiet it down.

The speedometer being off suggests that you have something other than the original 3.31 gears.

 

[carmine34]

I'm gonna get under it again this week to see if it's a 8.8 or a 7.5 but I think it still has the 7.5 pumpkin in it, that means this guy put traction-lok on a 7.5? This is just as aggravating as the 60s cars with Ford putting that weak small rear end in all the straight 6 cars! Uggg! You would think it would be cheaper to just mass produce the 8.8 and put it in all Mustangs. So how much noise are these cars suppose to make anyways? I get that there is a ton of road noise with these but this woaw woaw woaw noise at 60 + mph is driving me nuts! Are the clutch plates in the traction-lok rear end noisier at higher speeds? The noise is pretty much there at all speeds but worse at high speed. So if the lash is not set right or the pinion gear isn't set right I'm pretty much screwed? I'm no expert in setting up a rear end so my best bet would be to get a virgin 7.5 or 8.8 from the junkyard and swap out the whole thing? Are the springs perches and mounts different on a 7.5 than a 8.8? Thanks and I apologize for all the ignorant questions but I'm new the this generation Mustang and still learning.

 

[carmine34]

OK the plot thickens. Turns out the PO must have swapped the whole rear end out because now I have an 8.8 traction-lok rear end in a car that is suppose to have a 7.5 open rear. My next step is to put in some friction modifier in hopes that the person that set up the gears didn't add it and by some small miracle it might quiet it. So i'm guessing its a 3.55 and the original was a 3.31 so the speedo is off by about 5mph and the auto tranny is shifting a little too early. I see a lot of guys talking about BAMA tunes, are they expensive? From what I read it sounds like I can get a tune that will correct my speedo and adjust the shift points? Does anyone recommend these tunes? Do they screw up the computer and cause the check engine light to come on? Thanks,

 

[GriffX]

I don't have a comparison to other tuners, so....
The old generation of Bama tunes were horrible, but since they offer to send in log files for tune adaptation to your car I don't have any complaints. The good thing you pay only once and you can get new tunes if you changed something for free. I wanted to get a tune with an as-carburetor-like-as-possible feeling and they did a good job.
I never had a check engine light with their tunes.

For the noise it would be good to know if the tone changes between acceleration/coasting/deceleration. I guess you can save the money for the friction modifier.

 

[carmine34]

Noise is there pretty much there all the time the wheels are turning but louder after 40mph and nasty over 65mph. It is a droning sound with reverb, woah woah woah! Thanks for the info abut the tune! I think its louder on the passenger side but I think the wheel bearing is OK but I will check it again.

 

[GriffX]

I had a woah, woah in my diff and the pinion bearing had an uneven wear. Did the rebuild myself (longer story), it is possible as a first time job, but needs some research before. Good thing, you can usually drive without big problems despite the noise in the differential.