GS450hAU

@ColinBarber gotcha. So just do a drain and fill and no Techstream needed?

What is this " Line Pressure Off"? I don't have Techstream, do I need it? Can I do a drain and fill without Techstream?

@daveh6 and @ColinBarber can you please share how to do the transmission service, aka drain and fill. I recently pickup a 2018 GS450h and would like to do transmission service. I was thinking just to do a drain measure what came out and re-fill the same amount back in. Drive it around the block and redo the drain and fill two more times. Where is the refill hole on the transmission? I don't have access to the Techstream but have access to a laser temperature probe and can use this to measure the 30-40degC transmission temperature for the level overflow. Thanks guys.