Cyberspace Corvette forums breeds dummies at times and right now it has convinced C8 owners in flushing, draining and filling the DCT fluid
by replacing the DCT drain plug at bottom of DCT with a shutoff valve replacing the plug and adding a hose to it

So problem is to use that for filling the DCT fluid has to be put in a container that air-pressure can be added and then back force the fluid into the DCT

Dummies did not think as the DCT has an expensive fluid filter as seen below and it will be directly in the path of that fluid under pressure forced
to back flush the filter and push the trapped crap in filter back into the tranny.

Also depending on how much air-pressure they use could damage the paper filter and would not be known the DCT is then functioning without
a functional filter and worse if made of paper could rip up and carried throughout the fluid around the DCT

Filter at this time is not cheap and not easy to buy one for around $200.
Also a good chance if a cheap shutoff valve is used that the handle for open/close of valve pops open and drains all the fluid out without owner even knowing
it until the DCT craps out.

Time instead should be to take the engine aircleaner setup out one time and add a hose to a coupler to replace the top fill plug with a fill hose connected to that
and have hose long engine to end within engine bay so in future simply take a hose cap off, add a funnel and fill without having the jack the C8 up

One comment / question about this. You wrote

"draining and filling the DCT fluid
by replacing the DCT drain plug at bottom of DCT with a shutoff valve replacing the plug and adding a hose to it"

I think there may be a misunderstanding here. The write-ups I've seen are putting the shutoff valve in the normal fill plug hole, not the drain plug hole. I'm not sure I see how adding fluid through the fill plug, even under modest pressure, is going to cause back flow through the filter or damage the filter.

Note that I'm not planning on doing this anyway, but I was wondering if you could comment.

Thanks.

I have seen images on the 2 quart fill of C8 DCT where suggested is using either the fill or drain plugs to inject 2 quarts of DCT fluid into the DCT
Really makes no difference if the fill one is used as seen is right by the DCT filter and doing this using air pressure can cause that pressure
through the DCT filter and I doubt it can handle pressure like that

Imagine a mistake and using 125 PSI for this type of fill process

Also have seen that only the whole left side of C8 be jacked up at a high angle
The car was not designed for that and could cause a weight shift/load and break something

I am first hand in that being doing as having driven 1,500 plus to race at ORR out of Texas
I had the local Chevy dealer then replace the engine oil

I then went to practice, was running over 160 MPH, went to slow down and C4 ZR-1 about flipped over and only decades of racing was I able to get car stopped

Got out of car to find Mobile I engine oil covering everything from front all the way to back end, including both left brakes soaked in oil and the tires

Turns out the damn tech at dealer did the same, instead of proper jacking of car they only jacked up the left side so car was titled up high causing shift/.stress
which broke a weld of external oil cooler

I still say it is a one time job to add a fill hose to top of DCT so hose then is placed where it can be reached easy in future fills,
car on the ground and no need of any compressed air being used.

One image example on how close the DCT filter is to where the OP suggests the fill be done:

Thanks for your thoughts.

Your Welcome RJMeyer

I do not think with the costs of a C8 for people to take a chance that the DCT filter could get harmed and cause problems
or come apart under pressure and parts of that flowing through the DCT as will not be cheap to fix

Also not sure I'd want some added shutoff valve for any reason partly opening and once fluid is hot or with 2 extra quarts of fluid lowing out
Or some GM dealer tech doing some repair or maintenance seeing that valve and voiding DCT warranty

My hunch is this was not just for racing but late in Q/A or design testing some DCT thermal problem was found and GM to save money thinks with just cruising
the issue is less to happen

I'd say any C8 best to add the 2 quarts, not going to cause any real loss in fuel mileage