Hype

So before I get flamed, I did use the search button and got a varied response from transfer case, to output shaft to a hurt gearbox. So looking for any insight as to where I could put my efforts in trying to accurately diagnose the issue without taking parts out and stripping for the wrong reasons.

Let me explain the situation and hopefully someone can help point me in the correct diagnosis path.

Picked up an evo 9 gsr with a broken transmission, stripped teeth on 2nd gear, had a spare 6 speed which I had installed on the car.

I picked the car up from the mechanic and then drove the car around 20miles to my friends wheel shop to get the camber and alignment set. When the car drove onto the ramp the technician called me over to inform me of a leak under the car. Upon inspection it turned out to be the ACD bleed nozzle that was not fully tightened, so I had been losing ACD fluid for that 20 odd miles. I limped the car back to my house where I then did the foot to floor with ignition on to cycle the ACD lines. It drew alot of fluid into the system and frothed / bubbled into the reservoir, having to refill the reservoir 4 times in the process.

To cut a long story short I though all was fine and went for a 80mile drive to which a nice gearbox / diff / transfer case whine started to develope, when I got close to home the sound got increasingly louder. I got home and put car on the ramp where I drained the TC fluid and rear diff in the attempt to see if the fluid was dodgy or missing or had leaked out. All was at the right levels. It then got suggested that I had airlock in the ACD system which was causing the humming noise from 20km/h onwards which gradually got more intense as the speed increased. I bled the system and founda few airlocks in the system. Took the car for a drive and the sound stayed the same.

The evo mechanic that installed the gearbox took the car for a drive today and he suggested that there is a faulty bearing in the gearbox. Another friend says maybe the wrong gear oil used. I have a reason to believe it may be a transfer case that's on the way out.

Before I start taking parts out again that might not be the cause of the issue I'd like to maybe hear any advice or theories as to what may be the issue. The list of drivetrain mods are the just Megan Coils, Carbonetic Triple plate, stock drivetrain other than that.

I will be changing transmission fluid tomorrow just to see if the oil is whats causing the noise. Because the car was dead quiet when I collected in an within 100miles of driving the car went to being very noisy. I will try and attach a video of the noise tomorrow to help.

Any help, insight, expertise, possible points of diagnosis I missed would be greatly appreciated. Thank you

RGV250

The increasing noise probably indicates that some damage was done. Can you tell where the noise was coming from? Closer to the engine=gearbox(?) or closer to rear of car=transfer case(?).

Anyway, after you drain the transmission fluid tomorrow; smell the fluid to see if it has a burnt smell to it, and also measure the amount of fluid again to see if its the correct amount.

Hype

It mostly sounds like its coming from the rear of the car when you are driving, but if you put your head near dash it sounds like its more in center of car by the transfer case. Should be added that noise is there in neutral but not as pronounced, with clutch depressed it goes away.

I will take a close look at the oil that comes out of the transmission tomorrow for any odd smell or any abnormalities.

Hype

Here is a video of the sound, i changed oil, noise got slightly better, oil was fine but had a very slight hint of metalic pigment.

https://www.youtube.com/watch?v=voiE...ature=youtu.be

Doesnt seem to make the noise in first, or when on decell.
Video was done in 6th gear with on off throttle, 2nd - 6th same noise just pitch changes.

Sil'vr-Boi6

iTrader: (26)

I think I can speak as this happened to me back in 2009. I took my VIII for a service at a shop; parts weren't tightened, bolts were missing. TC fluid leaked near dry - it seized the TC on the highway! The noise was exactly like that in the video. It first was slightly quite in less than 5-8miles when I initially heard it, the noise amplified and TC seized and blew internally. I'm sure others will chime in and confirm. The infamous whoooooo and high pitched shrieking incident.

Drain the TC fluid and report back; you should see metal in it.

Hype

I will be pulling both gearbox and transfer case out on Monday next week.

The transfer case fluid when I drained it was the right amount, very dark in color though, no shavings in the oil, but there was a metallic sheen to the oil.

Changed the gearbox oil and there was no filings or any abnormalities with it.

I have subsequently done around 200miles and the noise hasn't gotten better or worse. Will have a better idea once its out of the car next week. Hoping its not the transfer case, but I think that's being mildly optimistic on the matter.

Thanks for advice thus far, will update once its out the car.

Hype

An update and a thank you to all who replied.

It was transfercase failure.

The main seal on the case was perished which caused gearbox oil to flow into the transfercase which caused the premature wear on the pinion gear.

Will post up pics of the transfercase gear wear, it wasnt bad but it was on its way
Upside means rebuild time. will cryo treat it for longevity.

DViper0020

Bump. I'm in for pics. I picked up a IX earlier and it sounds like mine has the same issue.