Transmission fluid is leaking from around coupler nut on the transmission. The rear seal is dry around the outside of the coupler. Is there a seal or gasket behind the nut?
Don't think there is a seal there. When assembling it should have had a sealer applied to the shaft/flange. I alway's do put some there,same with the vibration damper in the motor,sealer keep's oil from migrating down the shaft/keyway and leaking.
Grub
Google velvet drive transmission,I just did,found a few service manuals in pdf form. Did not read them,just downloaded for future reference.