The old Bolens factory seemed to change the types of trans fluids yearly. It seems that some have Ford type F or GM Dextron transmission fluid, others have 10 weight hydraulic oil, and some even have 10 weigh motor oil. The fellow that I know that was a Bolens dealer has said to replace them all with Hy Trans oil, no matter what is in there. The problem that I have, is that I don't know what presently is in there, so changing it completely is the next step. I know that transmission fluid is red, and motor oil honey colored, but the clear stuff is baffling to me. I have 3 of these Bolens left and they all should be changed. I am going to sell them and would like to do the complete service before they go to new owners. At $25 for 6 gallons, it will be a inexpensive "peace of mind' for both seller and buyer...