Hi, i'm new to this so sorry in advance if I do something against the rules! anyway I need to replace the oil seal around the shift shaft in my lower unit. I noticed that the shaft itself is rusted pitted. I ordered a new one of these as well. apparently they are now stainless steel but used to be regular steel. my question is can I just pull the old one up and slide the new one down or do the lower unit have to come apart? its an old pre alpha drive (1978 I believe) with a 165 inline engine.