Sorry to start yet another subject, but i keep thinking about the tranny filter.

I partly disassembled the housing and noticed it is just a thin mesh filter, then attempted to shoot air down the long O ringed tube to no avail. Then tried to blow air through the tube with my mouth, and either it is very very plugged or closed off because i could not get air through and forgot to breath and blacked out and hit my head on my bench.

Can anyone tell me what purpose the O ringed tube serves. Is it just to hold the filter? And I'm wondering if the fluid pushes up through the filter and then back down, exactly how does that filter clean the fluid?

It's a 79 eldorado biarritz with the th 325 tranny.