The size of your load can also play a role in which type of transmission is more favorable. Usually, vehicles with automatic transmissions will have a greater allowable cargo load than those with manual transmissions. This is because towing large loads with a manual can damage the clutch from shifting gears.
What size are transmission cooler lines?
The sizes can run from 5/16 inch to 5/8 inch so that DIYer will need to be careful to choose the right size hose.