what is this piece?

[jspaint97]

Redoing the seal on our t50d transmission, and noticed this part, is it supposed to have the cut in it because it is some kind of vent, or is it not supposed to have the cut?

 

[Mustang5L5]

I don't think that's an intentional cut. Looks like damage/dry rot. It is a vent as you said however.

F6ZZ-7034-A F6ZZ7034A Genuine Ford Part

Ford part # F6ZZ-7034-A F6ZZ7034A, Base part # 7034 at FordPartsGiant.com. Wholesale-priced and fast-delivered Ford parts Vent Valve Assembly.

www.fordpartsgiant.com

Discontunued part however. This one is specific to 96+ T5's but you can likely find an older Fox style vent to use as well

It's also used in the T-45 here