2015 Chevy Suburban that just had transmission fluid flushed and replaced and I notice some irregular shifts. Mostly when car is just started. Not every shift but more so a slow speeds.
Does it have an effect and need a few days.
Just changed Fluid 2 days ago.

 

Fluid change will not affect shifting. Using a flush machine can damage the trans. and it not recommended by GM on any of their transmissions.
Recheck you fluid levels also.

 

where can I find that they do not recommend?

 

It's been no flush machines for years now. Just drain and refill.
Flush has become a common term used as a sales tool. Every GM repair manual says no flush machines just drain and refill.

 

make sure the fluid level is correct.

not sure which trans you have but some will have an option to do a quick learn (not an adaptive reset) with a scan tool. The trans will do this on its own but will take a few days or longer.

 

Some FYI,
A flush is supposed to get the fluid from the torque converter out ...
It also does not get the accumulated "stuff" out of the clutch assys and valve body parts..
It can stir up the accumulated sediment in the bottom of the trans that can get into the valve body and sometimes cause them to bind or not work properly.
That is the reason why a fluid and filter change is recommended , because the sediment is cleaned out of the pan and is not free to circulate through out the trans.