Transmission leak at brake disc

[bwcollins 1]

My B-80 has a leak behind the brake band, appears it’s a slow leak behind the brake drum where it exits the transmission... Anyone know if there is a seal here? And is this leak common/easy to fix? Haven’t taken it apart and was curious, my transmission works fine, but gear oil will slowly leak out, it’s an 8 speed B-80 transmission 

[gwest_ca-(File Mod) 11,102]

There is a replaceable seal behind the drum. Here is the parts list

Pinned at the very top of the Transmission forum are crossovers for the seal numbers to available replacements.

 

Garry