I just changed the fluid in my trans and read many different articles about which fluid to use. I ended up using semi-synthetic semi synthetic trans fluid. The trans shifts very hard when cold but smooths out as it warms up. I've been considering adding a 1/2 quart of semi. synthetic 75/90 gear oil to maybe help it when it's cold. Any thoughts or ideas on this. I'm a little confused on why it would be hard to shift when cold.