Aftermarket Final Drive Whine

[c8Face]

I purchased a 2016 BRZ with the final drive already changed. I am not sure what part/ratio, but based on my speed, rpms, tire diameter, stock gear ratios, I am fairly confident it is the Mfactory 4.67 final drive.

Does anyone have this installed?

I am experiencing a whine from the diff that is not super loud, but definitely noticeable. I've talked to a few mechanics, and some say it's normal for an aftermarket FD, while others say it's too loud.

Any input from aftermarket FD owners (especially MFactory) would be appreciated.

Thanks.

[e1_griego]

What's the bushing situation? When do you hear the whine?

[c8Face]

Factory bushings. Whine can be heard from low speeds but is loudest at speeds greater than 35 mph. I've read this is "normal" for the Mfactory semi helical cut gears but I have no comparisons to reference. A friend who has never been in my car didn't even notice the whine until I told him about it. I'm considering having a diff shop check it out.

[mrk1]

I have had the MF 4.44 and yes they whined, MF said this is normal, how ever this is also to be expected on even numbered gear sets.

[nickmerronesucks]

I have stock final drive, with subframe bushings and diff bushings and I hear alot of whine. I guess its just added noise with the aftermarket bushings

[stevesnj]

Use higher viscosity oil. like..

[skye67]

I have the mfactory 4.67 years as well and there is Wine and cheese. this is normal for those gears and even going with Lucas higher viscosity oil make it quieter you'll still hear it.

[c8Face]

Thanks for the input. I had it checked out by a local shop that specializes in rear ends, and they confirmed the prior FD install was not set up correctly in terms of the backlash/pinion depth. Fortunately, the dealership where I bought the car paid the bill to have it reset it correctly. The the whine is still there, but it is definitely less than before (especially on the highway).

For those interested, I also contacted MFactory regarding the diff whine. Below is their response:
"Our final drives are made with the same tooth profile in that they are semi-helical. Also, the teeth themselves are larger, made for durability, which will also make some noise. "

[jcw99]

I have a new 4.56 Weir drive that has a slight whine to it. I notice it most in higher gears. When I let off the gas there is no whine.

[c8Face]

Originally Posted by jcw99

I have a new 4.56 Weir drive that has a slight whine to it. I notice it most in higher gears. When I let off the gas there is no whine.

I have the exact same experience. Most noticeable at highway speeds while on throttle.

[blackspike]

I also have the 4.67 MFactory final drive and it whines specifically at light acceleration.
There is a extra loud resonance at 37 and at 56 miles per hour.
At the first time my local shop don`t set the gears correctly (wrong pinion depth), second time the same problem... then i drove 450 miles to another shop which is specialized on the GT86 and the 4.67 final drive.
Now my gear setup is nearly perfect (slight deep conditions for best performance) and minimal backlash for best response.

Unfortunately the gears are still whining because of the wrong setup at the beginning.
They told me it will get silence after about 10k miles - we will see.

The MFactory gears arent polished and they are cut different from oem (semi helical - it is a compromise between verry loud straight cut und silent helical), so they will also whine when the setup is correct but not that loud.

My drive pattern:

[Mim]

I have the Cusco 4.556 and can't say I really hear any whine to be honest. Not sure if it helps, but the workshop I used advised to use only Castrol 85W-140 diff fluid (if it ever needs changing) and that's what they used on my install.

Could also be down to the gear set being genuine Toyota parts so may be designed to simply run quieter? - http://www.cuscousainc.com/catalogse...esult/?q=4.556

I was also given strict instructions for the run in process. No way to tell if those were followed prior to you taking delivery of the car in this case though I guess.

[blackspike]

The 4.556 Cusco final drive is full helical cut like the oem final drive.
85W-140 diff fluid is a good advice, it help to reduce the whine but don't expect wonder.

[skye67]

The gear whine is a noted side effect of M factories gears. I would have gone with another gear set but I was made an offer I couldn't refuse on this one I have my car now. I got them cheep already installed in a diff. I don't mind the gear wine, I think it sounds kind of cool.