I'M CHANGING THE TRANSMISSION OIL IN MY INBOARD BOAT AND IT SHOWS SIGNS OF RAIN WATER?

Question

Some told me to fill with diesel then drain then fill with oil? necessary?

Answer 1

If water in the trans only 2 ways to enter trans went under water or trans cooler leaking> No luck with rain water or you left the fill plug out> And no diesel as it will not mix with the oil or fluid> If there was a lot of water than fix the leak drain flush with oil run drain fill with oil run and check for more water intrusion>

Answer 2

   The best way is to change out oil cooler first; that is the main way water enters the tranny. Looks like a strawberry milkshake. Then change out fluid till it is clean again, with new trans fluid. This will take three or more changes; more if their is a reduction gear on the back end. If the tranny went under water, you would have a big mess in the bilge, probably a scum line from oil as to how high the water was. Then you need to change out any electrical parts that went under also. Like the starter, solenoids, ect. Good luck! Yes you do need to remove the water from the tranny, or there will not be proper lubrication to the parts inside, and will cause failure! If you find that it did sink, take to a shop, and file a insurance claim!