Ford 555 XL, I believe 1981. Having trouble with transmission slipping. The front tires have been lifting off the ground, not steering. I read about transmission having a screen to clean. I drained the fluid and took the 4 bolts to open a cover plate but all I saw is what appears to be a bleeder tube and nut. There was some debris in the cavity behind the plate but it is dry and nothing else I can see. Is this the screen I’ve read about? Any suggestions please?