Just need to know if that is what should be used to seal my NP205 to my TH400?? There is no gasket, and it looked like some sort of Silicon when I pulled them apart.

Thanks,
Steve

There is a gasket available but you can use silcone in a pinch.

they came from the factory with a gasket. this gasket was a double sided ahesive type gasket. it was used during assembling of the vehicle. if you don't want any metal to metal contact, use silicone.

is the 400 version 205 similar to the 465 version?
the bearing retainer snap ring thickness must be accounted for in the adapter recess
I think that on the 465 you must use a gasket to allow the snap ring to fit into the recess
measure it to be certain

on my 400/205, there was a rubber ring in a groove on the adapter.

The O ring is on the trans side and the gasket is on the t-case side.

Yeah we just used silicone on a 400 to 203

used sicilcone on same type of set up worked fine
saved money:D