Did a search and found some conflicting answers to this. I had a factory installed th350 and 203. I removed the 203 and replaced it with a 205. I now have leaking trans fluid coming from the adapter plate. The adapter plate has a machined lip that I cleaned and made sure that there were no chips between the two. Some of the answers I found while searching was that the th350 and 203 combo came with a rear seal in the trans output. I haven't removed to confirm this and I do not see any of the trans fluid making it into the 205 case. But I also haven't driven it since there are no drivelines. When I installed the 205 I did not put any sealant or gaskets on the adpater between the trans and adapter. The adapter was already installed on the transfer case and it does not leak. Do I need sealant between the adapter and trans? Do I need to replace a seal in the rear of the trans? Is the space inside the adapter suppose to be filled with ATF under normal conditions?