Keven Nguyen 
2017 Toyota Sienna Minivan XLE Premium 8-Passenger 4dr Minivan (3.5L 6cyl 8A)
The new 8sp Transmission, it has problems!
 2017 Sienna, XLE 5,255 miles.I noticed a light whining sound during drive/acceleration about a day or two before the first breakdown.  The whining sound comes on and you can hear it faintly with the foot on the gas.  You don't need to engage the acceleration, just keep your foot on the pedal lightly and you'll hear the whine, once you let go, the whining goes away.We didn’t have any problem with trips closer to home, the farthest we’ve driven locally was about 40 miles.  We took our first of town trip on Friday, Feb 16th.  This trip was the farthest drive the Sienna has encounter, one hundred and twenty six miles, with a travel time of two hours.  After we got off the freeway with our exit, at the first stop light, when downshifting from 2nd to first, we heard a “clunk” and a jerked is felt.  Then another light, the continued “clunk” and jerked progresses, the intensity has increased.  It started to happen more frequent, at every stop light, the downshifting jerks, “clunk”, and pulls, sometimes it felt as if we were rear ended by the car from behind.  Then on the acceleration from stop to go, the van started to upshifts too soon, therefore, it didn’t have any momentum.  It was also slipping/not engaging in 3rd gear.  Over the course of the next 30 minutes, all the skipping, jerking, pulling, clunking, every gear change.  They were loud, and felt like we were hit by another car from the rear.  We were pretty much rolling on first and second gear, no 3rd gear, vibration on 4th…  There were no check engine lights, no warning lights of any kind.  Finally, the check engine light came on, then shortly, the anti-slipping light came on, then the failed safely brake came on, then it just wouldn’t go forward or backward anymore.  We barely managed to roll off to the side of the road from the intersection.  I, my wife, our 2 yr old daughter, and our 3 month old; we were stranded out of town, late after 7pm in the evening.I used Toyota Roadside Assistance and waited an hour and a half for the tow truck to arrive.  The van was towed to Stevens Creek Toyota for an overnight drop off.  It took the dealer several days figure out the situation and to get repair instructions from Toyota.  They performed two software updates on the Transmission ECU and the throttle body.  I was provided a loaner to drive while the van was being serviced.I had to clear my schedule the following Saturday and drive back to San Jose to return the loaner and pickup my van.  The refreshed van seems to be doing fine on all the short drive in town.  However, the problem started again after the long drive back home.  As soon as we take the first exit off the freeway, while coming to a stop, a ‘clunk’ and jerk from the downshift from 2nd to first gear is heard and felt.  This ‘clunk’ and harsh jerk was happening here and there, not as often as it did on the our first breakdown.  I  didn’t want to take any chances of breaking down on the road again, so I drove the vehicle straight to Maita Toyota dealer in Sacramento.  I took on another loaner and wait to hear from the dealer again.  I don't think the problem will go away from software updates, it's probably just a bad transmission design somehow, this is the first year of the 8sp transmission, so it is a real problem.  I still have to go through this problem a few more times, then Toyota will have to buy this back under lemon law.  Even though we love this car for the comfort, I don't want to deal with all the problems and wasting time anymore.  To summarize all this up:-	2017 Sienna 5,255 miles-	The bad shifting/clunking/skipping gear/missing gear seems to happen after a long drive 1.5-2hrs, after the transmission gets hot.-	First sign of problem is whining noise-	Second sign of problem is downshift into first gear, when coming to a stop.-	3rd and continued sign of problem is more downshifts and upshift felt and noise-	After a few more lights of the continued sign, get ready to pull to the side and call for tow.