So last time I did my transmission fluid and rear diff changed I filled both ATF-Z1 and apparently there was an update saying that your rear diff is suppose to be DPSF and transmission is suppose to be DW-1 now. Well I didn't know that (went by using the service manual) That was about 20,000km already and now I'm wondering do I have to do a full flush or can I just drain and fill and just live on...?

 

As long as you followed the service manual you're good to go.
ATF-DW1 is a backwards compatible replacement for the transmission.
DPSF is replacement for the Diff but the old fluids are still acceptable.

 

Just Did mine when i bought the car with DPSF fluid last month.

Its a updated fluids thats all. Next change use the new stuff unless you really push the car. I have not read anything from honda saying why this fluid is better yet!!!

 

Ah ok cool. I guess I'll just do the drain and fill.

 

And I am not persuaded that DPSF is better than the original Z1, as DPSF was originally specified for the *different-type* of rear-diff in the Honda CR-V, not the SH-AWD type rear-diff. And I belive that RedLine brand D4 is better than Z1 for either a trans or rear-diff.

You can read more of my opinion, and that of others (in another referenced thread) using D4 in TLs, here:

https://acurazine.com/forums/showthread.php?p=14847924#post14847924