2017 SR5 Transmission Fluid Change - Manual Says Not Needed?

I've done some research here on TW and it looks like people have been referring to "the manual" as their source for why they changed their transmission fluid. On both the 60,000 and 120,000 mile maintenance interval description of my manual, it says to "Replace automatic transmission fluid," but only if this special condition applies: "Extensive idling and/or low speed driving for a long distance such as police, taxi or door-to-door delivery use."

I do not tow anything and my truck is 2WD. Also, my truck is a regular daily driver that is pretty babied - not a police/taxi/delivery kind of use.

1. Is there a difference between "replacing" transmission fluid (as prescribed in the manual) and "flushing" as I've seen others post about on here?

2. How can I know if my transmission fluid actually needs replacing or flushing?

 

Flushing uses a machine to connect [usually] to the cooler lines or similar and mechanically changes ALL of the fluid in the transmission. "Replacing" on the other hand, is usually just a drain & fill, meaning that you only actually change ~1/2 of the fluid. There is a lot of speculation that the pressure used in a '"flush", especially on transmissions with old fluid, can be detrimental, causing contaminants which are settled to circulate and potentially damage the valve body, etc.

Opinions vary widely; irrespective of what the manual states, unless it specifically states NOT TO, I would recommend doing a replacement at about the 100K mark or less, and about that interval thereafter.

 

Lifetime fluid is BS.

This guy's videos are GOLD. Here's one that applies to your question...straight from a long time Toyota master mechanic;

 

I do a drain & fill every year. takes about 3 quarts. Use a measuring container and replace what ever you drained.