Reverse won’t engage when cold

Hi, I have a 2011 Sequoia 4WD with 150k miles; I’ve done all maintenance by the book, driven primarily on highways for road trips across this great country and this week, out of the blue, reverse would not engage, noticed that once oil was at operational temperature it worked so reluctantly took it to a Toyota dealership and no surprise within seconds the diagnostic was: you need a new transmission….last maintenance on the tranny was at 100k when I drained the fluid, so I thought maybe fluid was due (although recommended is every 60k). Yesterday I drained the fluid (as opposed to flush) and it seemed to do the trick as reverse started working well however, I wanted to check in this forum if anyone has had a similar experience

 

Are you sure the fluid level is correct?

 

Yes, 4 QTs