'18 3.73 PP Diff whine

[HourlyB]

More audio from driving around normally;



Also having a issue with the left (driver side) rear brake being very hot and smelly, while the right brake is cool and doesnt smell. No handbrake/e-brake warning or obvious noise either.

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[shogun32]

Also having a issue with the left (driver side) rear brake being very hot and smelly

your piston seals are twisted an/or your parking brake return spring is broken/seized or pistons are not retracting in general. Have a shop take it all apart and figure out which set of problems you have.

 

[HourlyB]

your piston seals are twisted an/or your parking brake return spring is broken/seized or pistons are not retracting in general. Have a shop take it all apart and figure out which set of problems you have.

Could that also be causing the vibration, or just the heat/smell? The vibration is constant, but the heat is only ocassional.

 

[HourlyB]

So I did, and they ended up seeing that a nut was installed out of alignment. They realigned it, and handed it back.

Just realized, it was the pinion nut that was out of alignment.

That cant just be reused, right?

 

[HourlyB]

I hate to keep refreshing my own thread, but I have no idea what to do.

I'm not even sure if it's the diff any more, some people have described a similar feeling (again, in writing) vibration being from the driveshaft, and other people saying a IRS subframe brace would solve it and other still saying dropping the engine would help.

And another symptom has emerged yet; I get rough shifts occasionally even if the clutch is fully depressed. Typically shifting from 2nd into 3rd gear. Also the transmission has made a loud thunk noise when shifting into gears, again not every time but occasionally.

 

[SilverUri]

Took it back to the shop, they replaced both the bearings and the diff fluid. (I believe they replaced it with Spectro 75W-140, but I'll confirm the grade. They also said that they did not add a LS additive)
They solved the first noise, but now there is either a new or still a noise. And it is distinctly gear sounding.

I recorded it any made it into a video. Anyone have any idea what's going on now?

Hi, did you find the source of this sound and any solution?

 

[K4fxd]

Typically when gears start making noise the only solution is to replace them.

 

[HourlyB]

Hi, did you find the source of this sound and any solution?

Did not, and my solution has been to simply bear with the noise. The car already has so many mods from stock on it, gear whine is the least of the problems.
It has been to a couple of track days, and I've replaced the diff fluid a couple times as insurance. Noise hasn't gotten any worse or more noticable.
It is what it is, at this point.

 

[SilverUri]

Did not, and my solution has been to simply bear with the noise. The car already has so many mods from stock on it, gear whine is the least of the problems.
It has been to a couple of track days, and I've replaced the diff fluid a couple times as insurance. Noise hasn't gotten any worse or more noticable.
It is what it is, at this point.

Check if this sound is familiar to you.

 

[HourlyB]

Check if this sound is familiar to you.

It does not really; again, the sound is a whine, not a roar. It just sounds like gears not quite interfacing properly, but they are.

Just how it is. I'm not spending more money on a snipe hunt.

 

[shogun32]

Anyone have any idea what's going on now?

Perfectly normal. It's what happens when you lock out all that damn jelly rubber.

I have the whiteline cut out and replace bushings on 3.73 gears. If you go for Steeda/bmr pucks you get similar and if you get the harmonics just right a very loud version of that (mechanics call it singing) till you move off the resonance frequency.

 

[shogun32]

Also the transmission has made a loud thunk noise when shifting into gears,

When at rest, ya? Normal. The drive shaft is hitting the combined tolerances when the clutch drags things into tension. Just because your clutch is on the floor doesn't mean there is no torque on the input shaft. Just not enough to move the car.

 

[SilverUri]

It does not really; again, the sound is a whine, not a roar. It just sounds like gears not quite interfacing properly, but they are.

Just how it is. I'm not spending more money on a snipe hunt.

Check out this video, maybe this is it.

The point is that I have a similar sound as yours, but much louder and I have been diagnosing it for a month. If I find something, I will let you know.

For now I blame diff pinion bearing.

 

[shogun32]

Check out this video, maybe this is it.

Right so that guy is a friggin idiot. And using an impact wrench on bearing install?!?

 

[shogun32]

The point is that I have a similar sound as yours, but much louder

Is this another crashed car gray market import?

What mods have you confirmed have been done to the IRS and diff? Not saying it's not a bearing.

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