flyingriki.... I went to a new local shop that is reputable about a month ago. Did a pan drop, new tranny filter/O-ring, refilled with Toyota WS fluid. I was surprised that it took 5 quarts but drove it home anyway. I had an odd feeling in the transmission at mid-range so I decided to get smart on the transmission drain pan. I couldn't believe it. 10 years of ownership... numerous transmission services by my trusted mechanic (out of business thanks to Covid) and I was convinced that after 180K miles my transmission was shot. It make a whirring noise and seemed to slip around 15 miles per hour. I was so pissed! Rather than go back to a shop and argue in vain, I decided to check this out for myself. Since it is 90 degrees here in the lower Keys anyway, I started the truck from a cold start and drove .25 miles. I parked the Yota on flat ground and took out the measuring drain plug. Hours of You Tube videos showed me that the plastic straw that runs up the center of this drain plug is ideally level with fluid at about 110 degrees of temperature.
So... what came out of the drain plug? Over a quart of (fortunately) very nice looking red ATF! The flow stopped and I replaced the plug. I have since put over 1500 miles on the truck and have had zero sensations of the mid-range noise/surge that was there before I got the transmission level correct.
Lesson to be learned? Don't simply jam as much fluid in the fill hole as possible like that shop did with my truck. It will overfill! Open the drain and fill plug and fill with genuine Toyota WS fluid until it starts coming out. Close up everything. Warm the engine/tranny to 110 degrees. It is difficult, but necessary. Open the drain plug and let it level out at that temperature. Done.
Toyota - FAIL.... your customers want a transmission dip stick. So sad that these are now scoffed at as "old" and "fuddy duddy".
Off topic - In trying to help my mother maintain her 2015 Volvo V60 small wagon, I popped the hood to check out the battery which is on its last legs... first time under the hood. No oil dipstick. None at all. I spent quite a bit of time searching for it. Apparently, the infotainment system can be manipulated to check the oil level under certain conditions. Seriously? No dipstick? What could possibly go wrong?!?!