Well the drain and fill was done. It was and interesting (and stressful experience).
1st Drain and FillWhen the first drain and fill was done the fluid was a very dark brown. That convinced me (and my mechanic) that another drain and fill would be needed as we were changing out just 3 of 6.6 liters. My indi shop ended up refilling the tranny from the top hole. They did not fill from bottom and rely on"Stand Tube" to set proper level. I am not sure why they opted to do it this way. So they were setting level purely by pouring back in the same amount that came out.
This made me concerned. Could they have spilled some when draining? Could they have drained warm fluid and put in cold fluid? Then the cold fluid will expand to a higher level. I just did not feel comfortable at all about this.
2nd Drain and FillAfter the first drain and fill I found this information in Fiat repair Manual.
MoparŪ AW1 when new is red in color. The fluid is dyed red so it can be identified from other fluids used in the vehicle such as engine oil or antifreeze. The red color is not permanent and is not an indicator of fluid condition. As the vehicle is driven, the ATF will begin to look darker in color and may eventually become brown. This is normal. MoparŪ AW1 also has a unique odor that may change with age. Consequently, odor and color cannot be used to indicate the fluid condition or the need for a fluid change.So the dark brown color of fluid drained may mean nothing. So based on this I decided that I would have a 2nd drain and fill done and stop there. After doing it twice my fluid would be about 70% new. At 87,000 kms it was good enough for me.
To make sure the fluid level was correct I bought a dipstick. This way the level could be correctly validated and I would rest easier. I think my mechanic was happy to have it as well.
https://www.amazon.ca/dp/B08YYLVTB7?psc=1&ref=ppx_yo2ov_dt_b_product_detailsSo that is that. The tranny feels good. I used to feel a very slight bump when coming to a stop when tranny went back into 1st gear. That is gone and overall I find the shifts are smoother. Very happy.
So at next oil change will be a coolant change and maybe an brake fluid flush.