Ill get right to it. Question #1: How many of you hear a decent amount of gear rollover (bearing noise) when your cluth pedal is out when sitting at idle in nuetral? Then when you push in the clutch it quites up.

Question #2 So I just found out yesterday that my IX has the launch function, so of course I had to go try it out just once. lol. Ive noticed that ever since that single hard launch the first gear whine that Ive had since day one/brand new has turned into a Jetsons Space Car kinda sound. Not really louder than it was originally but instead of the steadily increasing gear noise its a, well the only way I can describe it is a high pitch Jetsons sort of noise. My question is did I maybe crack a gear tooth or something on the launch? any idea what else might cause that sound?

And just for kicks what does everybody think of the stock 1st gear whine? Ive always thought it was annoying and perhaps a poor design.

 

I don't have any throw-out bearing noise on my 6MT.

As for question two.. can't answer that. Haven't launched mine yet (and what launch function btw?).

 

ive never launched my car so i cant answer number 2 but on number 1 im not really sure what whine noise it is you hear

 

to address #2, you don't have a launch function on your car. it has a lower rev limit to prevent you from doing excessive damage to the car if you launch it. think of it as a "stupidity prevention" function.

 

if youre sitting in the car on a perfectly flat road (so the car wont roll at all) put the clutch in and put the gear selector in 1st gear. Now pin the throttle to the floor. The engine will rev and stop at ~4500 rpms. At this point all you need to do is pull your foot off the clutch quickly and the car will launch quite effectively.


You can dwell on the semantics of what to call it but it is essentially a launch mode.

 

It's 5000rpm, and such a whine is usually a busted transfer case.

 

^^But I def. think you would be able to tell if your transfer case is busted, more so than just the noise.

Your probably just paranoid.

 

1. I have the same noise that you described in question #1 since day 1. I guess it's normal since I don't have further problems and I have 14000 miles on my IX.

2. I haven't launched my car, so not sure about this one.

3. That whine on 1st gear is normal as far as I know. It got louder with colder climates and usually gets quiet down when the car gets fully warm.

Since we are on the topic of tranny , does anybody know about humming noise when you release a clutch during downshift from 2nd to 1st and 3rd to 2nd? It doesn't make this humming noise if I rev-match.

 

ROK EVO what you are describing just sounds like decel noise

and for the OP

I experience a very low pitched whine when it's colder in all gears...it's only noticeable if I listen for it but I've had my car for 12k miles and it has never gotten worse so I'm not worried

 

I thought the 1st gear whine was caused from the straight cut gears?!?!

 

Probably true. Im gonna take it to a mitsu dealer and see what they say.

 

A major excitation source for gear whine is something called "transmission error" which has to due with the non-conjugate motion transfer of the gears. Superimposed on top of the gear's mean rotation speed are small higher frequency oscillations attibuted with the deflection of the teeth, assembly errors and gear tooth profile imperfections.

These small oscillations (due to the motion transfer error) create dynamic forces and these forces are then transfered to the shaft, bearings and then to the housing. The housing vibrates and acts like a speaker - the customer then hears gear whine.

Modifications can be made to gear teeth to try and minimize transmission error. However, minimizing transmission error usually only happens at a small range of loads. Meaning, you would still have 'large' transmission errors at other loads. Automobile manufactures can have a tough time minimizing transmission error since the transmission gears see a wide variety of loading (hard acceleration vs. cruising at leagal highway speeds). Other gearbox manufactures have it easy since their gearboxes may only operate at one load (an industrial situation for example). Also, be aware that the modifications to the gear teeth that are used to minimize transmission error are on the micro-inch level! A micro-inch is 0.000001 inches!

Most gear whine issues in automobiles occur at light loads. Unless the whine is truly a dynamics problem, the whine does not indicate that your transmission is going to fail.

Transmission error can not be totally eliminated, it can only be minimized (again typically only at a small range of loads). Therefore, gear whine exists but the degree of the whine is what customers usually complain about. Gear whine is probably more acceptable in a $10k car vs. a $50k car. If you really want to hear some gear whine, drive your car in REVERSE!!!! Since most people do not drive in REVERSE all of the time, the manufactures save money by not modifying the tooth profiles of these gears.

Hope that helps...

 

1 - normal.
2 - search 2step, and how did you launch it? If you just revved up to the 5k limiter and dropped the clutch then yep, you might have mess the TC up or the trans. Does it make this sound in all gears? And if so, does this sound get louder/higher pitch as rpm/speed increases?

First gear whine is normal and a part of this car. See RoadSpikes info ^

 

Dude you just brought back some memories of Physics class back in college...All of which always gave me a headache. Good explanation though.

OP: ANswer to 1 is i have a IX SE which does the same darn thing.

#2 ...i never launched it....nor will i ever!


I Hope it ain't broke 'cause you will have a heck of a time getting it fixed through

 

Sorry zwampy I'll keep my future explanations down to a less than grad school level