Whine noise under load and acceleration

[mini_fd]

It just doesn't end


Just last night I received a new noise to me. The whine or as some may call it a supercharger noise only happens underload. Whenever I press the gas pedal is when it begins. I can hear it louder behind the parcel shelf when I sat in the passenger side and had someone else drive. Here is a video

Under load acceleration:*


http://youtu.be/UuVYY_Vang8




I recently just changed the fluid in the differential a week ago
With new energy diff mounts. I have a turbo charged 5 speed 99 nb with a 04 msm rear diff and axles.

[mini_fd]

Any ideas?

[kung fu jesus]

Your diff is heading south. If you freewheel at a stop and as the car rolls a little forward then transitions to rolling backward, you may feel the driveline bind up a little.

[mini_fd]

Video 2:


http://youtu.be/PgnT91Pzlao

[kung fu jesus]

The last 10 seconds confirms that diff has some serious lash issues. It will go boom.

***edit... Where is the knocking and ringing coming from in those last 10 seconds? The diff or the driveshaft?***

[mini_fd]

We think it's the drive shift atm. The harmonic balancer looks like it's a bit loose. The rubber cross looking piece. Not sure of its the u joints or not. It's being towed so no more damage will occur beyond repair. First thing first the driveshaft will be replaced.

Bow it did look like at some point in life the heat shield above the shift where the u joints are sagged and interfered with the shaft. Not think it's the problem here as I bent the metal up out of its way.

[revlimiter]

The U joint on a drive shaft is super easy to check. You have to remove the shaft, but it's only 4 bolts.

Remove it.
Move the end all around. Is it notchy at all? Is there a click? If so, it's bad.

A good one will be perfectly smooth with no notch anywhere in the motion. And Miata drive shafts are not fixable. You have to either get a new one or get one built with serviceable U joints. Sharka has the later.

[kung fu jesus]

The DS is usually the culprit to a diff heading south like yours shows symptoms of. A few clues are the stiff u joints, the dampener on the diff getting wonky, and the sound. A few key points...Miata driveshafts aren't balanced, plus worn u joints, this will send a LOT of vibration into the differential, stressing the pinion and its bearing. That whine is the pinion getting out of spec, creating lash. The pinion will then walk and take out a few teeth on the ring.

Replacing the DS is one thing, and swapping in another one is a good cheap test, but I would be prepared for the diff to grenade. While you have the DS out, it would be prudent to check that input on the diff for play. A bit of rotational play is normal (to a point). Check for lateral and longitudinal play as well.

I don't mean to play Debbie Downer, but this isn't my first rodeo. :)

[mini_fd]

Okay well I might swap to a 3.9 diff then with a 6 speed. Plus it's easier to replace axles on a 3.9 rather then a msm. I'm just down because I liked using the beefier axles

[mini_fd]

It's the diff. A 3.9 and six speed is going in now.

[iKhanh]

don't mean to bring up a "dead" thread, but what did you end up doing with your old MSM diff? i just put mine in and am having to troubleshoot some noises of my own that isn't whining like yours.

[mini_fd]

We junked it. There were metal sparklies all in the oil. I couldve covered my body with all that glitter and walk the streets in key west.

Tell us what your experiencing.

[iKhanh]

I finally got around to swapping it in from a guy who crashed his Miata into a barrier, but said the previous owner before that had the diff rebuilt/serviced. Can't tell for sure, by when I opened it up like a year ago, the teeth all looked good.

I had both axles rebuilt. New axle seals in the differential too. Put the whole bottle of Valvoline 75w-90 (forget if it's synthetic or not) gl-5 oil into it.

So, the noise! It sounds like a something isn't turning smoothly; I can hear friction, similar to brake pads on a spinning rotor. Noise is present any time the wheels are spinning, even in neutral. It does get louder the faster you go. Very obvious when driving on a bridge or something with high guard rails or walls that echo the noise as you drive by. Maybe the noise goes away after 40mph, or just the road and wind noise drowns it out.

I have adjusted the rear brake pistons so that the pads don't touch, but it's still making the noise. I haven't pushed it hard yet during my test drives.

When I have the time I will take some turns and try to rule out the wheel bearings, but I'm pretty sure it's not them cause before the swap they were fine. I will drain the oil when I have time and take a look at the magnetic drain plug. I have a feeling there won't be much to look at since I've only driven about 15mi, the gear teeth looked good, and everything seems to engage smoothly..

[mini_fd]

can you hear the noise specifically in a higher rpm?
or can you sit in the passenger seat while some one else drives and put your ear over the parcel shelf?

rule out the fuel pump, i know its silly but if you have an amp that too.

[iKhanh]

I hear it as long as the wheels are rolling. My fuel pump never made any noise before. I also had the stock stereo off. I'll try to have someone drive it though. Hard to find someone I can trust with that responsibility though lol.

[kung fu jesus]

You should get a passenger or mount a gopro near the noise and take it for a spin, then share it on here.

Quick question...is the diff GL-5 compatible?

[iKhanh]

I don't have a GoPro =( BUT! I will jack it up and simulate the noise on video for you guys, and then another with my friend taking a video while I drive it. I'm gonna drain the oil today and see if I notice anything unusual in it like shavings.

Yes, the diff is supposed to be able to take GL-5, at least according to page 3 of the differential section of this link I'm gonna post here for future reference for anyone interested. https://docs.google.com/folderview?id=0B3YbfB30DxW0bEdwS0xSNGVXMzA

[iKhanh]

Okay! Noise is still there. Videos will be up soon when I have time/get home. Shook the wheels, no abnormal slop or play in the hub, so I think the bearings are okay. R&Red the diff oil. No metal chunks or shavings in the oil; it was super clean. On the magnetic drain plug though, yes there was some, but I don't think it's an amount to worry about, but then again, I forgot to clean it before I installed it from the previous owner so it could have been years and years of accumulated debris. Cleaned it this time though! I think the prop shaft u-joints were in good condition when I installed it though, but next time I get a chance I will take it off and move it around. I sprayed white lithium grease on the joints though and... The noise was there.

[kung fu jesus]

Are your axles fully seated into the differential?

[iKhanh]

I believe they are. Holding it as level and straight as I could, I basically shoved it in, and tried to pull it out with some force to double check if it was successful. No oil leaking anywhere. Videos are being uploaded now and will post here when done.
12317
here's the drain plug yesterday. Changed to Mobil 1 gear oil now.

[kung fu jesus]

That's a lot of shavings for only 15 miles. They look a little big, too. Without hearing the video, I would lay odds on the bearings in the diff.

[iKhanh]

my friend was recording on my phone while i drove.

Miata driving noise: http://youtu.be/sZ5HiZjoiXY
several times in the video you can hear a noise like something is winding/whirring down in speed

Miata driveshaft noise: http://youtu.be/CRyTlDm80L0
in this video, my friend is rotating the wheels by hand while i'm under the car. you can clearly hear the noise that sounds just as if the pads were touching the rotor. i'm not sure if it's the driveshaft, but it just sounds more apparent in this general location underneath the car.

i'm about to go to my Miata and disconnect the driveshaft and mess with the u-joints, and also rotate the wheels and see if the noise is gone. if the noise is gone after the driveshaft has been removed, would it be safe to say that it's the u-joints? i've read that the MSM driveshaft is the only Miata driveshaft that has serviceable u-joints, but that some people have still had it fail after service, and that they recommend just getting an aftermarket one from like 949 Racing. don't really wanna spend $300 though..

as for the shavings, i don't think that's only my doing. i forgot to clean it prior to install so that might have just been from the previous owner, or the owner before that. i will change the oil again after i drive it some more and see what it looks like then.

[kung fu jesus]

Videos are private, dude. You need to make them public.

***NVM, I see them now.***

[iKhanh]

oh yeah, ha, sorry, fixed. =)

[kung fu jesus]

I think I can hear the friction noise you are referring to. I can see in the second video, someone modified the balancer rather poorly. You even remarked the input looks a little messed up.

Is the dragging sound coming from the transmission, driveshaft, or differential in the second video?

[iKhanh]

Yeah I always wondered about that balancer thing you mentioned, but i've read elsewhere that it actually doesn't pose a problem.

It seems a bit more noticeable when I was under the driveshaft. My transmission never made that noise before the swap. But once I disconnect the driveshaft, I can further deduce what may be the culprit. Will update soon.

[kung fu jesus]

Does what remains of that balancer spin independently? I have seen those come loose on the Torsens and make a similar sound.

[mini_fd]

I've been told that spec miatas replace the balancer as soon as possible because of its constant failure. Now, when i applied finger pressure to mine, I did see it move a bit. But looking at your drain plug, that's a lot of crud. Was it sparkly or gritty looking?

I thought i heard the whining noise in the video and was like that's the same sound.

Before I say its definitely your diff, make sure the heat shield to the gas tank is not interfering with the drive shaft or the balancer.

[iKhanh]

Does what remains of that balancer spin independently? I have seen those come loose on the Torsens and make a similar sound.

What's left of the rubber on the balancer is stuck on there; doesn't spin freely.

mini_fd: Ehh, it was mostly gritty after i soaked up the excess oil on it. But if I decide to drive it like this, I'll drain it once again after some miles. And nothing is touching the driveshaft or balancer.

Update: With the driveshaft out, spinning the wheels still makes the same noise. I will post another video that's more or less the same thing. So that leads me to believe that my driveshaft and transmission are okay, as well as my axles. I am guessing it would be a bearing inside that's not rolling as smooth anymore. Anyone know if the bearing(s) inside are lubed by the oil, or are they closed and have their own source of lubrication (greased bearing races perhaps)? And what are my options at this point if my diff is the source of this noise? When I took it apart the case last year the teeth looked good, but I'm no expert.
Miata diff: http://youtu.be/HvKEo5o5ZMc

[kung fu jesus]

Yeah, that's bearings.

There are 3; pinion and two shaft bearings. You are going to want new seals, too.

949 Racing sells a kit for about $225

http://949racing.com/miata-diff-bearing-seal-kit.aspx

It is a bit involved and I wouldn't do it myself. I would start looking for a shop that specializes in differentials. Best guess, it's going to run you ~$400-700. Call around, though.

[iKhanh]

thanks for confirming my fears =( i don't know what i wanna do. i've grown attached to this diff because, well, it's a rare piece, but do i wanna pay hundreds more? or wait to get another LSD and possibly spend less, then be left with a MSM diff needing to get rebuilt? so depressing.

[Rogue]

Is it a Torsen or a Fuji?
I just replaced a Fuji in a Shinsen that sounded like that.
Looks like a common issue with them.

[kung fu jesus]

I was running numbers in my head for the repairs...this is how I broke it down:

Say the repairs are the ballpark 400-700, that is about the same price as a complete torsen swap (pumpkin, carrier, axles, driveshaft), but now you have a used torsen of unknown condition, not to mention the other pieces, too.

So, for roughly the same price, minty LSD or another unknown.

I would call around, though. You owe it to yourself to get the numbers and decide from there.

[iKhanh]

It's a Torsen.

Yeah I'm gonna ask around and see what kind of guesstimates I get. Thanks for everyone's inputs and stuff.

[kung fu jesus]

Fortunately, the Miata pumpkin is pretty easy to separate from the carrier, so labor should be less. I have heard of guys getting their diffs prepped for the racing season for around $300, so I hope the damage, monetarily, is light. :)