5MT Knocking

[Yasha]

Hi everyone, I have an 05 OBXT 5MT and recently I started noticing these knocking/clunking noise coming from the transmission. It first began a couple of months ago with just a small knock coming from the transmission if I aggressively revved the engine when in neutral, once I put the tranny into first, no noise. I know that it isn't coming from the engine because I have since put over 4k miles on the car with no knock detection from the accessport and it still pulls like a mofo. Recently what has started happening is it is knocking even when in 1st when I rev the engine but also, it intermittently knocks/clunks on idle when in neutral. If I put the tranny into any gear, it will stop knocking/clunking when in idle. I know fluids are all fresh ( changed around 9k ago) in the tranny and rear diff with subaru gear oil. Please if you have any thoughts, let me know. Car has wrx up pipe and the first cat in the downpipe gutted, running ACN 91 Stage 2 cobb tune but I live in MA so I put nothing but 93 in (just trying to preserve the motor for as long as possible). I never launch the car and have power slided in 1st like 3 times around corners. I rarely unleash the beans in 1st but I do a lot of aggressive driving. Ideas as to what the noise might be: I highly doubt its the throughout bearing because there is no grinding/shearing noise coming from the tranny. I am thinking it is input shaft or output shaft bearing, and also, maybe the reverse lockout dinging around. I was also considering maybe something having to the with the clutch placement is bad ( clutch replaced at 70k by previous owner, now has 148k) Please let me know if you have any ideas and if you think the tranny might blow in the next 5k.

[Max Capacity]

At idle in neutral with your foot off the clutch, the tranny is not spinning.

 

The clutch disc rides on the input shaft which has the pilot bearing at the FW and the input shaft bearing in the tranny. So it could be one of those two bearings.

 

http://people.csail.mit.edu/ilh/vacation/

 

Oh yea, if you can buy 93 load the 93 map.

 

Where in MA do you live ?

 

Motul Gear 300 is currently the best fluid for the tranny and diff's, the Subaru stuff I would not use. It's not like the old Extra-S.

[Yasha]

Hey, so what your telling me is a new transmission might be in order in the next year? The noise is vary in consistent, sometimes clunking in neutral and sometimes not. I will keep the motul stuff in consideration when doing my next transmission oil change.

When it comes to the 93 tune I really don't want to push it. Computer will do all the adjustments it needs if it sees more power is available. The engine has 148k and I don't how the previous owner drove...

 

I live in Maynard MA but am currently in school at Rochester Institute of Technology. We have a free bjs membership from the school so I go to the BJs 5 minutes down the road to get 93 there. Has 10% ethanol in it too so even higher octane than 93.

[Max Capacity]

My car has been on 93 all its life. Even when I have to get a tank of 91 up in NH or ME, I just drive it easier until I can fill it with 93 again.

 

At this time, your going to want to make sure the car is good to run all winter without issues.

 

Have you cleaned the MAF sensor and is the air filter clean ? Make sure you can see the orange tabs at the joint where the plastic intake manifold meets the TGV's. The older black ones can have issues when it get's cold.

 

The tranny can be rebuilt, you won't need to replace it.

 

 

Can you post a video of the noise showing your foot on/off the clutch and the noise in gear and neutral ?

[Yasha]

I have cleaned the MAF sensor and replaced the air filter last week. I just checked and I do have orange tabs at the TGV.

 

I tried to take a video of the noise but it wasn't happening today, maybe because it's warmer than usual today. I'm not too worried about the noise being anything catastrophic as the transmission still shift really smooth. Also, the noise is completely gone when you put it in gear.