Terrible Noises...

[Garrin]

I've had a slight "clunking" sound which I believe is the driveshaft because it has a lot of slack in it and I've read a few other cases where these cars experience that, and a constant "grinding" type noise from somewhere in the rear, possibly the diff, for quite a while now. I have it lowered on the Eibach Pro Kit and have the BMR adjustable panhard bar, so I was thinking maybe my pinion angle was off. I ordered and installed BMR adjustable upper control arm and mount and Eibach adjustable lower control arms. The pinion angle is right at -1 and the noise is still there but now with an additional rotational grinding noise. Sounds almost like an axle bearing or something and gets worse when turning to the right, which leads me to believe the left bearing is going out. I am going to adjust the angle down a little more to a -2, but I don't really think that will make the noise go away. Any ideas? 2013 SVTPP with 27k miles. I'm trying to avoid taking it in, but I think I'll be dropping it off at Ford Monday or Tuesday.

Also, it doesn't make the noise when the car is on the lift and tires spinning freely and there is no vibration at any speed.

 

[Silver Talon]

Good chance its the wheel bearing then. Mine has a similar issue now. Weaving the car left to right, the noise goes away after I turn right. Get it replaced before it sends a ton of bearing material through the diff.

 

[Garrin]

That explains the "rotational" sound, but what about the constant rubbing? It sounds more like it's coming from the diff. Could it be as simple as a front pinion bearing you think? If I have to have the whole thing opened and disassembled, I might as well go ahead and order some 3.73's...

 

[Silver Talon]

I don't see anything where you explained a rubbing noise. But you have to remember that the axle shaft turns into a tuning fork with the wheel bearing going out. It will send sound down the axle into the diff, and make it appear as there is more issues. Obviously until you open it up, you wont know.

Whats the rubbing noise you mentioned?

 

[Garrin]

It's a constant rubbing/grinding noise. It almost sounds like brakes when they are metal to metal, but it's not the brakes. And that noise has been there well before the rotating bearing noise. It sounds to me like it's coming from the differential, but it doesn't do it unless the suspension is loaded, zero noise on the lift with tires turning freely.

 

[LuuisHernandez]

People have heard similar noises from not tightening their lugs. Just worth checking.


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[Silver Talon]

Sounds like you will need to pull the diff then. The carrier bearings could be suspect. If the wheel bearing is bad enough to allow a lot of vertical travel, it could be torqueing the axle enough as it enters the carrier to be putting a side load on the bearings, and cause wear or noise. My 14 V6 with bearing issues, only had about 1/2 to 3/4 inch of play at the end of the axle, with it slid into the carrier, but no wheel bearing on the axle. With the car in the air, the axles will be unloaded, and riding on the bottom of the race, not top that would see more wear with the wheels supporting the weight of the car. If you pull the cover off, and the axles out, you can generally put a pry bar on the carrier to see if there is slop in those bearings. That's how we found wiped out carrier bearings in my old car, after doing a gear swap a few thousand miles before hand.

 

[Silver Talon]

That made quite a bit of noise. But it was more when on power, when coasting it was quiet.

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[Garrin]

People have heard similar noises from not tightening their lugs. Just worth checking.


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I read that on here somewhere. I'll check them again. Thank you.

 

[Garrin]

Sounds like you will need to pull the diff then. The carrier bearings could be suspect. If the wheel bearing is bad enough to allow a lot of vertical travel, it could be torqueing the axle enough as it enters the carrier to be putting a side load on the bearings, and cause wear or noise. My 14 V6 with bearing issues, only had about 1/2 to 3/4 inch of play at the end of the axle, with it slid into the carrier, but no wheel bearing on the axle. With the car in the air, the axles will be unloaded, and riding on the bottom of the race, not top that would see more wear with the wheels supporting the weight of the car. If you pull the cover off, and the axles out, you can generally put a pry bar on the carrier to see if there is slop in those bearings. That's how we found wiped out carrier bearings in my old car, after doing a gear swap a few thousand miles before hand.

Thanks! That makes sense. I think I'm just going to take it to Ford and have them do it under extended warranty. I don't trust myself to do a job like that.

 

[merkyworks]

Just something to keep in mind. Changing from factory rubber bushings to aftermarket poly bushings will increase road noise.

 

[Garrin]

Just something to keep in mind. Changing from factory rubber bushings to aftermarket poly bushings will increase road noise.

Yeah, I can definitely tell a difference in noise from the bushings, but this is a different noise, or noises really. It sounds pretty bad. Going to Ford Monday. I’m done messing it. Apart from opening up the diff, there is nothing else I can do at this point. This whole thing is just turning into an ordeal.

 

[Beercules]

Make sure you clean out the diff cooler circuit also.

 

[biminiLX]

These 8.8s need some help. Could be a bent axle. Have you ever raced it? If the rear does need to be rebuilt, even if under warranty, it’d be a great time to do a gear swap. Good luck.
-J

 

[Garrin]

Well, took it in and they recommend replacing the whole unit. I decided that if I'm going to change it, I might as well do a Moser or Strange 9". But then when I go to order it they said I have to change my driveshaft too because the 9" will only work with the 1350 yolk and my car has the one piece carbon fiber shaft with the flanges. I wasn't prepared to drop an additional $1000-$2000 on a driveshaft. Now I'm not sure what to do. Should I just stick with the 8.8 or what? I swear, if it's not one thing it's another....

 

[biminiLX]

A 9” is great upgrade, especially if you drag race.
You can get a shaft for about $1000 and sell yours for $500.
I’d have Ford put in a new 8.8 and then decide if you want to upgrade.
Do you drag race?
-J

 

[Garrin]

You’d go back with the 8.8? I do race a little, but very rarely. Maybe twice a year.

 

[biminiLX]

If any drag racing is involved and you plan on keeping the car, go with a 35-spline Strange bolt in 9”.
First I’d let Ford fix it under warranty (try to buy them a FRPP 4.10 to throw in while it’s apart-seriously) then sell the stock 8.8 complete for the 9”.
You’ll be able to reuse your stock brakes, and I was very impressed it was a true bolt in from Strange. Only change is a new driveshaft, and the car will drive like stock but actually hold up to the power.
-J

 

[Garrin]

If any drag racing is involved and you plan on keeping the car, go with a 35-spline Strange bolt in 9”.
First I’d let Ford fix it under warranty (try to buy them a FRPP 4.10 to throw in while it’s apart-seriously) then sell the stock 8.8 complete for the 9”.
You’ll be able to reuse your stock brakes, and I was very impressed it was a true bolt in from Strange. Only change is a new driveshaft, and the car will drive like stock but actually hold up to the power.
-J

I'm probably just going to order the 9" but I was thinking of going with Moser over Strange. Do you think Strange would be a better option? And I'm kind of leaning toward the True Trac, it's between that or the wavetrac. I'm out of factory warranty, but have an extended warranty bought through the dealership I work for, so I think I can get them to pay for it and just avoid doing it twice.

 

[Silver Talon]

Get the 8.8 replaced under warranty, then have the 9inch built. A good Shelby 8.8 will be worth some cash, and you'll be able to offset the cost of the 9 inch.