Turbo 350 205 T/C Leak

[blownz]

My 72 K5 is leaking trans fluid into the T case. I have had it apart twice and still leaking. The first time, I had the seals backwards. My second attempt, I took apart a virgin 205 and adapter. The original seals were in there and I took the seal to the parts house, they matched, I re-installed correctly. Thought I had it licked.... wrong! After checking on the Net, I found an old posting from us,

hdfslf wrote on 11/30/2008: Actually there are 3 seals. Been there done that. There are 2 seals on the outside diameter of the coupler (these are the likely leak path). Pay attention to the direction they are installed since they are backwards from what you would normally see. Third seal is a thick o-ring on the NP205 input shaft which seals with the inside diameter of the coupler.

Does anyone know what size o ring or have a part number for it? I am getting ready to take apart and would like to have the part on hand.