I just bought a 1979 Chevy 1 ton pickup with the SM465 4 speed transmission. This is my first manual transmission, and I'm teaching myself how to drive it. 
I understand that this is a big, old, slow, heavy duty truck transmission and it's not like driving a Honda. The trans is somewhat sloppy getting into gear, but that is to be expected on something 30 years old. It's also a little hard to get into gear sometimes, though part of that is me learning to drive it.
Anyway, I haven't fallen in love with this trans. Thinking hard about swapping in an automatic. Should I spend the big bucks and get some good synthetic oil in this thing before I decide I don't like it? Can it make a noticeable difference in shifting performance? (current fluid is unknown)
I understand that this is a big, old, slow, heavy duty truck transmission and it's not like driving a Honda. The trans is somewhat sloppy getting into gear, but that is to be expected on something 30 years old. It's also a little hard to get into gear sometimes, though part of that is me learning to drive it.
Anyway, I haven't fallen in love with this trans. Thinking hard about swapping in an automatic. Should I spend the big bucks and get some good synthetic oil in this thing before I decide I don't like it? Can it make a noticeable difference in shifting performance? (current fluid is unknown)
)
My only other option is to order Reline or Amsoil at about $10/quart plus shipping. I'm SO mad the local Amsoil dealer went under!
Anyway, since it's SO expensive and I have no idea what fluid is in there now, (could be 30 years old for all I know) do you think I should do a quick "flush" using cheap fluid like Coastal for a few hundred miles? Or for that matter, are there any good cleaning additives for manual transmissions? I'd be too afraid to try a cleaner in an auto...
