ATF WS - Drain/Fill Question?

Which dealership is your normal dealership? You mentioned JBT which is where I bought my '16 Prius. I've been pretty well happy with them but when it comes to time for a flush I'm not forking out $300!

 

Does draining the tranny fluid actually empty most if not all of the old oil? I know in some previous slush box "auto trannys" I owned, one would need to drain X % then top up X%, drive around the block, then redo again until fluid was clear.

 

Near as I can tell based on contaminants and viscosity changes, there is about a 15-25% that can not be drained. Successive changes:

• 1st = 15%-25%
• 2nd = 2.25%-6.25%
• 3d = 0.34%-1.56%

It appears the initial, manufacturing debris is the bulk of what we find. After the third change, the oil settles down to a constant rate of viscosity shear-down with a period of ~100k miles.

Bob Wilson

 

Has anyone performed a DIY change on a 2016 yet? I'm looking for advice/guidance/experience...