There should be no more "crud" in the transmission oil
cooler than the main engine heat exchanger
unless there is a problem or insufficiency in the raw water
strainer system. They are connected in series - one after the other - with, sometimes the water
pump in between.
- - Depending upon what the "crud" looks like - sea life or leaking transmission oil
- will determine what needs to be done.
- - Cleaning
it using the same techniques that will be used on the main engine
heat exchanger should remove any "sea-life" and then a pressure test will show where there are any leaks
between the raw water
side and transmission oil side.
- - It is not uncommon for the transmission oil cooler (heat exchanger) to fail before the main engine heat exchanger due to lack of zincs in the transmission oil cooler raw water path.