T18 w/ 4wd gaskets
Bronco Graveyard sells gasket kits for both T18 and NP205, they also have full rebuild kits if you want to dive deeper.
It was the NP205 gasket kit that had the gasket for between transfer case and transmission, but there are also seals in the tail shaft housing and input of the transfer case and that is going to keep gear oil out of the tailshaft housing. The gasket is just extra insurance there. You could get away using a thin coat of RTV or similar sealant there too.
The build thread I have linked in my signature has more detail about rebuilding both the T18 and NP205 which I did for my truck last summer. Neither rebuild kit for the transmission or transfer case included the seal I needed for the tail-shaft housing though and that had to be ordered seperately. The seal number needed is in my build thread.
https://www.ford-trucks.com/forums/1...l#post21349249
SKF 15773 is the number on it.







