Leaky transmission Volvo Penta 2003

[ekhar]

I have 1986 Volvo Penta 2003. I seem to have leak from the place where transmission attaches to the engine. The transmission is
kg120B-120SB. I have been trying to find the parts.. gasket and boot but cannot seem to find them on the web. Where do I look to have these changed.

In my search I came upon a MOODY owners website and there is a big complaint about SPLINEs on pre-198 2003 engines.... What are
splines? How does one fix them?

thanks
Gene