Transmission Filler tube Gasket

I see where the transmission filler tube gasket/seal in not available anymore ....so what do we do if this starts leaking like mine has just started ?? Is there a replacement or something we can do to stop the leak ?? I hate to tear it apart...and be stuck with leaking fluid. Anyone with information would be greatly appreciated 2000 Impala 3.8 Automatic:runaround::runaround::runaround::feedbac k:

I see where the transmission filler tube gasket/seal in not available anymore ....so what do we do if this starts leaking like mine has just started ?? Is there a replacement or something we can do to stop the leak ?? I hate to tear it apart...and be stuck with leaking fluid. Anyone with information would be greatly appreciated 2000 Impala 3.8 Automatic:runaround::runaround::runaround::feedbac k:
Did you check RockAuto.com. I see one for the 2000 Impala 3.8.
CHEVROLET 2000 IMPALA 3.8L V6 Transmission-Automatic Dipstick Seal

Delco Part #1259475, $7.57 on Amazon. $2.06 at Rock Auto. HTH