Should I do a progressive drain and fill (drain a little and fill a little over 2-3 different sessions (as opposed to a full flush)) on my 160k mile 2015 chevy silverado? It has been inconsistently hard shifting or racing between gears for about 10 months (again, inconsistently). It seems to be slowly getting a little worse.
I get that drain/fill runs the risk of dislodging debris or otherwise immediately ruining the existing transmission. But the fluid is basically black looking and it sounds like the transmission might be on its last leg anyway, so I figured it can't hurt and it might help (???). But do you guys have any insight? Thanks in advance.