raredesign

I just drove away from the shop with 4.10 gears (Ford Racing, not Motive) freshly installed. I am honoring the breakin period, and the dudes at the shop did a great job as far as I know, as they have plenty of experience installing gears.

There is absolutely no whine, but I am getting a noticeable brushing sound, especially when I press in the clutch and free roll. It is a pulsing sound, not continous.
Very similar to if you had a warped rotor, but is only on deceleration, and again, is more noticeable with the clutch depressed.

EDIT: I said that it is noticable, but please understand that it is faint. Still I find it annoying.

Please help. I am going to call the shop tomorrow, but wanted to know if this is something that will go away with the break in, or if I should have this checked out.

Thanks,

stang910

Don't know that gears make the noise your describing, but sounds like when they pulled the axles they accidentally bent the brake shield and its rubbing your rotor.

raredesign

That would be fantastic if that is the issue!!! I was hoping it was something simple, but also questioned if it was the bearings since my car only has 17k miles, he used the original. I will post back the findings.

mygt500

I am wondering if the dive shaft has anything to do with it.....just throwing ideas out there

doctorstrobe

Do you have any suspension mods? Lower control arms, etc? That can transmit more noise up into the cabin.

I can hear my gears also, but I have aftermarket LCA and UCAs, with rod-end joints on one side. I can hear everything going on in the diff...
It doesn't sound like anything is wrong, it just sounds like gears meshing...

I've just put dynamat all under the rear seats and into the trunk area a bit.
It definitely helped to knock down the noise but I can still hear the rear...

raredesign

I called the installer, and he told me all the specifics of how the install went, and he states it was flawless, but did say that he would gladly check it out. He wants me to wait first, because he doesn't think it is a gear or bearing issue, and was right in line with stang910's reply...thinking it has to do with the brakes.
After driving it a bit, it should quiet down.

raredesign

Well, it has been a little bit now, and I have to say it is definately more than a brush. It turns out to actually be the gears, but I am told it is normal.
The guys that did the job are really nice, and have already taken it apart and remeasured, etc, but they said the pattern matches perfectly, the measurements are exact, and the install is rock-solid.

Both the owners took it for a ride, and I even took one of them for a ride, but I guess the sound is only annoying to me and my wife. Also, though the sound is there all the time, it only seems to become really pronounced once it is warmed up.

The best way to describe it is that it sounds like engine braking, but coming from the gears. It is not a loud howle that I have heard people have problems with, but it is still there, just as loud as the tire noise, and a little less than the engine breaking.

Maybe it is just me, but I am one of those guys that once something annoys me, I can't get it out of my head, so I can hear the pulsing whine even with the radio on. Funny thing is, I think I can actually feel it in the pedals and shifter too. I don't think this is all in my head; rather I think I am just paying extreme attention to it...and I know how the car was before hand.

Nevertheless, the gentlemen exlained that now everything is moving much faster so slight change should be expected.
They are experienced with the loud whines and they said this is nothing like that.

Another issue I am noticing now, is in 5th, at about 60mph, if I ever so slightly touch the gas pedal, there is about a centimeter or so that it moves and that is just enough to hear a difference in the way the rear sounds.
It produces a steady gross sounding fast growl if that makes sense. But it is different than the exhaust note, because that is going on at the same time too. (I have SLP's by the way, but this cannot be them unless there is a leak somewhere, but I don't hear it at any other time).

Anyway, I get wierd about things, but I am almost frustrated enough to not even want to drive it.

doctorstrobe

Is there any way for you to record the sound and put it on Youtube or something?
It's hard to tell whether it's a bad or good noise just from descriptions...

I know what you mean about when you lightly touch the gas.
At around 60 mph mine make a very very slight high pitched vibration. Some kind of resonant frequency is my guess...

raredesign

I wish I could record it, but I don't think it will be clear in the middle of all the other sounds.
Does anyone live in Rochester, NY?
I just feel bad constantly going back to these repair guys. They even took it up on the highway and shut off the engine so they could listen to just the roll.

What kind of damage am I doing if there really is a whine, and something is not right? Will this be able to be fixed later by another shop, etc?

raredesign

So it turns out that friction modifier was never used, since they went full synthetic. We are going to give it a shot anyway, and run full synthetic with friction modifier and see if that quiets it up. Maybe that has something to do with the noises apparently getting worse when it gets warmed up.