Does anyone know what purpose the little white plastic cap plays on the top of the TC in the middle of the square plate?


This is a picture of someone else's but mine has a smaller steel cap on it that appears to be like a little valve like it lets air in and out, I think the plastic caps has broken away and fallen off, is it important?

 

It's the breather/vent.

 

Ok thanks, by the way when I pulled the TC and dissassembled I found nothing wrong with the ring and pin and bearings were smooth, even though there was grey in the oil and the decel noise thing going on, I found nothing in the TC that could cause it, I took the bits to a Evo tuner and he said it all looked and felt fine and it could be a bit of throw off from the clutch plates slipping but those looked in good nick also, baffled me. I'm now thinking input or output bearing in the gearbox

 

Do you have an actual gear guy looking at the gears? Gray/black fluid coming out of a hypoid gear diff is bad. I've changed fluid on Evo's that had fluid with 50k miles on it and it was still fairly clear. I'm still leaning towards a smoke ring and pinion. Bearings can be fine even if the gears are bad.

 

he owns a workshop, I got him to check the ring and pin gears, he showed me with a straight edge that they were both in excellent condition, no sign of obvious wear that would put color into the oil. Along with all the bearings which seemed to tick over like silk, he couldn't see a thing wrong with anything. I am baffled what would be throwing metal into the oil

 

A straightedge? On a gear with curved teeth? You're looking for galling on the face of the teeth. Unfortunately its all but impossible to see it in pictures, have to look at it in person.

 

he said he'd love to sell me another ring and pinion but it looks like its hardly got any wear on it so I didn't really want to shell out a grand

 

My breather cap is semi-loose, it isn't supposed to be correct.