Coolant and Transmission Changing Frequency?

[J&P]

The owners manual on our Volvo D1-20 recommends changing the coolant and transmission fluids every other year.

We average 40-50 hours of engine time per season.

Neither is an easy task due to access and the concern is that I might be doing more harm than good (which is always a concern of mine in performing preventive maintenance). And I can't remember the last time we changed either fluid on our cars.

I am curious how often other people change these fluids on their engines and is it worth the effort to stick with the manufacturers recommend maintenance schedule.

Note: Oil, oil filter, and fuel filters are changed every season.

- Phil

[bottomscraper]

I change the TX fluid every year. AF is tested every year and changed every 3-4 years on spec. Which reminds me I need to
do both before it gets real cold out...

Th hardest part about changing the TX fluid is not overfilling. It doesn't use very much and goes from below the bottom of the diip
stick to overfill very quickly.

Transmissions are expensive, TX fluid is cheap.

[Maine Sail]

I change the TX fluid every year. AF is tested every year and changed every 3-4 years on spec. Which reminds me I need to
do both before it gets real cold out...

Th hardest part about changing the TX fluid is not overfilling. It doesn't use very much and goes from below the bottom of the diip
stick to overfill very quickly.

Transmissions are expensive, TX fluid is cheap.

Ditto, I change it yearly. Many of these gear boxes, Hurth specifically, use "thrust washers" ANY metallic shavings wind up grinding on them and EAT them. Keep the fluid clean and you'll be fine.

Change it often..

This thrust washer is supposed to be flat with NO ridge in it!!