IRS Transmission Final Drive (Trans Flange) Seal, 9.5mm Width**, '69+ Type 1, 3

This is the seal that prevents fluid leaking out from behind the axle flange on an IRS transaxle on the side cover.  To replace it, you'll need to remove the seal in the middle of the axle flange to access the retainer clip.  Remove the clip.  Slide the trans flange off.  Then replace this seal.  Don't forget to order a new seal for the middle of the axle flange, too!  Sold each.  You'll need 2 to do both sides.

** NOTE:  You'll want to measure the seal in your specific trans.  Some require 9.5mm wide seals, some require 15mm