Transmission ATF replaced 3 liter of 6.7

The ATF change with removal of oil pan and filter only replaced 3
liters of 6.7L capacity. Given that the ATF change intervals are
168000 km for normal use, is it worth doing a drain and fill with 3L
more (I still have 2L leftover). I realize it is a diminishing return.
Just wondering if it is necessary.

 

Yes, it's worthwhile. That's why the manufacturer recommends it. The
manufacturer is well aware that all the fluid in the transmission will not
be changed. If you'd like to get close to changing all the fluid, you can
have a flush (fluid exchange) service done.

 

OK. I will drive for a week and then do a drain and fill with 3L more
and stop there.

I am unable to find a flush service that will use SP3 ATF. Not sure if
there is any need to be concern over the possibility that the fluid
exchange operation could dislodge the filter due to high pressure.

Thank you for all the help. My car maintenance is near done and it is
running noticeably better.

 

There's no need to do the service again until the next maintenance
interval. You've already done what's expected. Doing it again will take
you from about 50% new fluid to about 75% new fluid. If you're doing the
work yourself, it's cheap and really can't hurt anything, either.

Your filter bolts onto the valve body. It cannot be dislodged unless the
bolts are loose.

Anyone that does flushes can do it with SPIII. They may not wish to deal
with the dealer to get the fluid, but in that case, you could purchase the
fluid and take it in yourself. But don't think you need to do this,
either. Once you've replaced the filter and put new fluid in, you've met
the maintenance requirement.