Humming sound from tranny.

[90 GSX]

I was racing responsibly at the local track the other night. I don't do clutch drops but I get out of the hole very fast. What I usually do is slip the clutch at ~5000 rpm until I see the boost come on then I dump it. That way it's not a complete shock to the driveline. During the first run, I heard a couple thumps at the top end of first gear (sounded like axle thump but my car doesn't have axle thump) and when I went to hit second it was like there was a wall blocking me from getting in. I don't know if that was clutch hydraulics not keeping up with my shifts or what but it was disconcerting. My slave leaks a little but I have a brand new master and slave that will be gonig in with my act2100. Ever since them I've been hearing this light humming sound coming from then engine bay/tranny. The car drives perfect, clutch feels just fine although after I raced it didn't feel so good haha (ACT is going in soon). You only hear the noise when cruising in gear. If I push the clutch in it disappears. With the clutch out, you hear it all the time after about 1500 or 2000 rpm in any gear. It sounds the loudest in first gear. The noise sounds sort of like a bearing, but I don't know how 1 moderate launch could really damage a bearing, especially since I replaced the tranny not too long ago with a freshly rebuilt one. Could it be the t-case? How could I find out? Would low fluid cause that problem???

 

[dsmclipse97]

might be the TOB... mine rattles alot, especially if your clutch is on the way out

 

[Talonman92]

With all the mods done to your car, and if you "use" the car for what it is... I bet your tranny is just wearing out. The"wall" you say you felt going into second gear is most likely the synchro going. When my second gear went out, I could only shift into it at LOW rpms. If you tryed to do it at 3k+ it would just deny you.

Changing the tranny fuild, installing the slave \ clutch combo might not help the condition of the tranny itself.

I doubt it would be the Throw Out Bearing, because he said its making a humming sound only when its in gear, when its out of gear it makes no sound.

Could just be your tranny getting tired?

 

[dsmclipse97]

The clutch going would also make getting into gear a pain in the ass.. especially after you just pounded on it by letting it slip. If it was the TOB, it would stop making noise when the clutch was depressed because it is no longer engaged. plus you said the tanny is pretty new? I somehow doubt its the tranny. I have my money on a bad clutch.

 

[Talonman92]

Well if your slave is leaking fluid then it wont be long before you put your car into lets say third gear and it just never comes back out. Happend to me on a busy street of course... I accelerate up to 3rd gear and then I put the clutch in and try to shift and nothing. one of the worst feelings in the world right there, clutch just decides to STOP working right then and there.

I might not be understanding something right, isn't the TOB used only when you are depressing the clutch pedal down to the floor? So if you were just driving around in fourth gear with a humming sound how could it be the TOB when its only used during shifting?

 

[dsmclipse97]

You only hear the noise when cruising in gear. If I push the clutch in it disappears.

my car does the exact same thing and ive been told countless time that it was the TOB. My clutch is brand new too. Luckily its not anything damaging its just annoying. im not sure if thats the case here but it sounds similar. it means the TOB is rattleing when its NOT being used, like when the clutch is engaged.

if you search it im sure you will find like 100 threads on it. just my .02 cents.

 

[90 GSX]

Thanks for the advice. The noise on my car seems to go away after you depress the clutch but only after the engine slows down. The clutch is stock and is on its last leg. Could it still be a TOB?

I think I'm just going to drive until it breaks. Hopefully it's not the tranny but knowing my luck...

 

[Echo5Zulu]

I highly suggest swapping in a new clutch and seeing if it still makes noise. Personally I dont think its the tob because of when the noise happens. Im almost thinking someone shimmed it improperly and a bearing is being eaten away. You could crack the case and check it all. Its not too bad I did it for my lsd instal and had a bearing ready to blow. You want fix this before it grenades and the tranny is all done. Could also very well be a bad syncro because you said you hit a wall shifting, you can easily check those visually too.

 

[95talon_in_ma]

Does it make the same sound when in neutral?
If it's the tob, it will only make noise when your clutch is depressed.
Here is a really good pic and explanation.
http://www.carcare.org/Manual_Transmission/throw-out_bearing.shtml

Since you said it's making the noise all the time, my guess is eits either the clutch\flywheel broken. Or those 5000RPM dumps took a toll on that tranny...
But since you AWD, you can't rule out the diff or even the axles themselves.
I had an axle last year that went and it never clicked or anything. It just started out as a low whirr and slight vibration. After two days, the thing let loose on me on the highway...

I think I'm just going to drive until it breaks. Hopefully it's not the tranny but knowing my luck...

Deciding to wait until it breaks has nothing to do with luck...But once you explode the tranny, it can't be rebuilt. Just do the clutch and at the same time pull it apart and inspect it... It may just need a syncro and not an entire rebuild. But if you leave all those shaving floating around, you'll definitely need a rebuild soon...
Good luck!

 

[andymoraitis]

I suggest not mentioning street racing in a public thread again...

 

[VelocitàPaola]

I suggest not mentioning street racing in a public thread again...

I concur.

 

[90 GSX]

Thanks for the advice but it was just a couple harmless stoplight runs around the corner from my friend's house, I mean the local track... not street racing by any means. But I'll keep that in mind.

I have raxles axles in my car. I have never regreased them, how often should it be done? Could that cause this whirring noise?

Could it be the axle carrier bearing? What do those do when they go bad?

I know that it's something in the front, either axles, carrier bearing, wheel bearings, or transmission bearings. I can almost garuntee it's not anything from the t-case back. I may not have time to do this clutch for another week at least... If the noise starts getting worse I will stop driving the car. I also believe that there is nothing broken... the noise sounds like a bearing.

These trannies are piece of junk. I had 2 crack on me already. And now this one has a bearing going out.... I can count the number of launches I do per year on two hands. What the hell gives?