Hey all so I bought the car with a JWT Clutch and lightweight flywheel. As many of you know when you do this you can have the "cement grinder noise". Over the weekend I took out the transmission fluid and replaced it with mobil1 fluid and filled it all the way to the top in the tranny(used hand pump to fill it, made it overflow slightly). The shifts are smooth and there is no transmission noise!

 

Filling the gearbox all the way to the top is a bad idea. Once the oil heats up, it will expand and you will lose a bunch of it through the breather/overflow valve and get gear oil all over the place.. plus you'll lose some power as a result of the extra drag in the transmission. Then once the oil level has dropped a bit as a result of the overflow, you'll get foaming in the gear oil which will cause more of the oil to spew out the breather, and at some point the foaming could cause the oil not to lubricate the gears as well since manual gearboxes generally rely on oil climbing the gears or splashing up to lubricate the top half of the transmission.

In all likelihood, the only reason you're not hearing the cement mixer sound now is that it's being drowned out by all of the fluid in there. The cause of the noise is probably still in there and doing its thing, but you just can't hear it.

I would drain the oil back to the level it's supposed to be at (flush with the filler hole). It's usually OK to put a little bit extra in, but not as much as it would take to fill it all the way to the top.

 

Yes I know, after letting the transmission run a little bit in my garage I let some of the oil out. It's stil above the level but not full, this is what Michelin does for all of their tire test cars.

 

i hate that noise! I think im gonna be doing this this weekend!

 

I have it like 3/10's over the recommended amount now. Don't let it run for long at all, it was just for a tiny amount, don't want it to heat up too much.