Just recently had a 3.73 gear swap done but there seems to be a whirring noise on deceleration. Granted still breaking them in but should this be a concern?

 

Installing Rear Axle gears is an Art. Only the Few Can Do Them Correctly. That Has Been My Experience During 35 Years Working at Ford Dealerships. Getting Bad Gears From the Factory in New Cars Has Been An Issue with Ford in the 8.8s For Years as Well. Gears Bad out of The Box Can Also Happen. I would Get Them Checked Out Sooner Vs Later. Comments Also Apply to 7.5 Diff in V6 to Lesser Degree as Far As Issues Observed.

I am Listing Shop Manual PDF for Refererence.

KC

 

Some gear whine is pretty common with the 3.73 gears. Some people say this can be eliminated if the install is perfect; however others say that there can be some whine regardless of how perfect the install may be.

I had mine installed by an installer with an excellent reputation around here, he double-checked the mesh pattern, and they still whine a bit. I called some other shops in the area to see if they might be able to do something with it, and they recommended that I go to the guy who already did the install, because he's the best around.

It should not do any damage, assuming it isn't horrible, but the noise can be a bit concerning/annoying. I'd suggest you talk with the installer about it.

 

Added a video of the sound let me know if this is concerning or I’m just overthinking it.

 

I did Not Like What I Heard.

BTMO!

Everybody Chime In!

KC

 

FYI the humming sound is the noise.. the rest is the rocks from the road!

 

it is hard to tell from the recording, but that does not sound like "normal" gear whine to me; what I have heard is higher pitched than that ... I think that is worth a trip back to the installer, take a road test with him and ask him if that is "normal" for his installs

 

Hey I just found this in another forum if this helps. "I did get a negative report from the installer concerning the Ford racing gear he said it had burrs on it straight out of the box. He said that it could cause the rear end to whine when you let off it but should go away after the break in."

 

How Many Miles are They Saying to Break In?


KC

 

It didn't say other than run it until the sound goes away!

 

wouldn't that be nice (if the sound went away) ... let us know how that turns out

 

If It Were Me I would Check For Metal Shavings at 500 Miles.

BTMO,

KC

 

And yet your installer went ahead and installed them knowing full well the gears have burrs in them anyhow? If it were my car, I'd be demanding a full refund, otherwise, my next step would be to schedule a hearing before a magistrate in small claims court!