A Youtuber that I trust recommends Valvoline MaxLife Multi-Vehicle (must be multi-vehicle) full synthetic trans fluid for both the GM and ZF transmissions. I know how that sounds, taking advice from a Youtuber, but I've watched at least 30-40 of his videos and he seems to really know his stuff. His name is Nathan's BMW Workshop if you want to check it out.
This stuff.
https://www.walmart.com/ip/Valvoline...allon/15125768
I keep going back and forth on what to put into my truck in the near future. I got a smoking deal on 8 liters of ZF fluid ($80 with mechatronic sleeve) locally so I might order 2 or 3 more now to do the service. Originally I was going to use that Valvoline for sure.
Just thought I would pass it on. More information/choices are always good. Right?