transmission oil and cooling system flushing on 1997 Honda Civic

I have been told that Honda does not recommend flushing out either the transmission oil or the cooling system fluid. Just replace what gravitationally flows from an open drain valve. Is this true? The car is manual shift, has 140,000 miles and never had either of these services performed.

Asked by for the 1997 Honda Civic
I agree with Matt.
Anyway there is nothing to be gained from trying to flush a manual transmission, it is mechanically configured different from an automatic transmission and changing the transmission oil when the car has been driven to get the oil hot will get a sufficient amount of oil out of the transmission.
Thanks to both matt and autotechpat for their quick responses. I'll proceed on the basis of their answers.
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This is absolutely true. Honda does not recommend using flushing machines on any of its vehicles or any of its components.