Trans/Diff noise. Will it go boom or naw?

[TDavis]

So ever since I installed the mFactory diff in my trans. I've had a werring/rotational noise when on the throttle. Only from about 40-65mph, otherwise its not present. On the highway at 70+ I don't hear it, same with anything below 40mph. I shimmed and did everything per the workshop manual when we installed the diff. New bearings/bolts etc. when installed. Me and my dad thought it may be normal just because of how many more gears that the new helical diff has compared to the stock open diff so its going to make some noise.

At one point I couldn't stand it anymore and 400-500 miles later I took the trans out again to see what was up. No bearing material and the races all looked fine. So I just said fuck it and have been dealing with it ever since.


Any input on this? This happened right after installation of the diff. Wasn't doing it before unless coincidentally the input shaft bearings wanted to shit right after diff install but it doesn't sound like that type of noise. At least from the videos I've seen on here with that problem.

I really do not know what to think on this. It's been like this for the past 18,000 miles and the noise hasn't gotten worse or louder. Also have put a few track days on it as well with no issues. Trans fluid looks normal when I've changed it the past couple times.

 

[jessemon1106]

My silver fiesta went out with a bang. I bought it wrecked and I split the tranny open, and I didn't follow any recommendations. Reused everything minus a new half of a case. To fix the broken tranny mount. It lasted a bit over 10000 miles when I noticed a whining noise when going over 35 or so. It was shortly after that my transmission exploded. Some have a whine without problems. I suspect mine was me not knowing what I was doing or just some other damage in the tranny from the wreck.

 

[Woods247]

Mine has always whined a bit as well. I use Motul 300 gear oil. What are you using?

 

[TDavis]

Mine has always whined a bit as well. I use Motul 300 gear oil. What are you using?

Ravenol 75w-80

I know nobody likes to assume but I would've figured something would've happened by now if it wasn't normal since I've put a few track days on it and 18k miles

 

[TDavis]

Any insight?

 

[M-Sport fan]

Mine has always whined a bit as well. I use Motul 300 gear oil. What are you using?

That stuff is thick enough to actually cut back on a bunch of whine/noise in a gearbox/transaxle.

But then again, the beating you put on it on track probably mechanically shears down even that fairly viscous fluid to a Ravenol MTF-2 level, especially in mid summer sessions.

 

[foodtruck]

> normal just because of how many more gears that the new helical diff

Those gears are not rotating against eachother when you're going straight. The only thing you could possibly hear is some clunks when the torque is reversed and the gears are pushed in the opposite direction and take up the available slack.

Can you record the noise? FWIW, I've read somewhere that it could be the passenger's side axle support bearing; there's a specific process of clamping it down and the post stated that it was not done right and resulted in uneven pressure and consequently the noise.

 

[TDavis]

> normal just because of how many more gears that the new helical diff

Those gears are not rotating against eachother when you're going straight. The only thing you could possibly hear is some clunks when the torque is reversed and the gears are pushed in the opposite direction and take up the available slack.

Can you record the noise? FWIW, I've read somewhere that it could be the passenger's side axle support bearing; there's a specific process of clamping it down and the post stated that it was not done right and resulted in uneven pressure and consequently the noise.

Pretty positive I did the axle clamp right but it doesn't take much to do it again since you don't have to do anything else to get to it. I can try re-doing to see but I highly doubt its the problem. When I first installed the LSD and I heard the noise I took the trans out 3-4 different times to make sure I shimmed it properly.

Also, the noise probably isn't clear enough to get over a recording.

 

[foodtruck]

Also, the noise probably isn't clear enough to get over a recording.

Eh, might still be worth a shot. Also if you have access to chassis ears, they can help to pinpoint more effectively where it's coming from.