The Impreza's tranny seems a little noisier lately

[Legacy777]

I'm not sure how long it's been like this, but it seems kind of recent that I've noticed that the transmission sounds noisier. The AWD drivetrain is noisier compared to others, but this just sounds noisier. More then likely the noise is coming from the front diff.

My main thought was that tranny cocktail I used had worn out all the EP additives, since it was a mix of fluids, including synchromesh. I had about 7500 miles on the gear oil. The old oil still looked good, I saved it in a milk jug since it was synthetic. Anyway, I changed the tranny fluid last weekend to some dino valvoline combo 80w90, and a qt of 75w90, and the sound is still there. I can't tell if it's less or not....but it's still there. Shifting seems to require a little less effort.

Only other thing I plan to check is the tire pressure. It's possible the front & rear tire pressure is too close together, and promoting more drivetrain noise.....instead of having the front tires having a little more air.

Thoughts?

[entirelyturbo]

Is everything GL5?

The noisiest my transmission ever got was when I was using straight GL4 GM Synchromesh.

How many miles?

[BAC5.2]

The noisiest my transmission ever got was when I was using straight GL4 GM Synchromesh.

That was the sound of your transmission eating itself alive.

Any cocktail including GM's synchromesh is bound to give you a headache at some point.

Swap in some Lightweight Shockproof mixed with your favorite synthetic (I like Motul Gear300). If your tranny can be saved, that'll be the concoction that'll do it.

[Legacy777]

It's all GL 5 now.

Car has 141,000 miles on it.


Before hand the tranny cocktail was more or less uncle scotty's mix, which had LW shockproof in it.

When I drained the oil there really wasn't any metal chuncks on the magnet....

How much LW shock proof would you use? 1 qt? More?

[Legacy777]

I put in an STi trans mount this weekend, and the noise is definitely more noticable. Actually one of the trans mount bolts just stripped the threads clean out of the transmission casing. I hand started the bolt too....

Anyway, it sounds like gear teeth smacking together.....almost like straight cut gears. When I depress the clutch, the noise goes away, and if I release the clutch slowly right at the engagement/disengagement point, you can hear the noise slowly go away, i.e. the gears slowly spinning down.

I believe the noise has always sort of been there, it was just recently that it became noisier.

Any suggestions, other then just to drive it until it pukes?

I may put the stock trans mount back on to quiet it down. What about lucas marval oil or something? Anybody use that?

here's a pic of that bolt
http://www.main.experiencetherave.com/s ... P_8224.JPG