Two problems related to transmission noise have been reported for the 2015 Honda Odyssey. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2015 Honda Odyssey based on all problems reported for the 2015 Odyssey.
Purchased at 45,646 miles. Noticeable juttering at 15-40 mph, most notably from 25-30 mph and driving up hills faint whining noise. Dealer checking software update on transmission. Noticed on freeways and city streets.
I purchased my 2015 Honda Odyssey brand new and have done all the maintenance on time with Honda. My sliding doors do not stop if something is in the way. I have had multiple times where a child has tried to go in/out while the door is shutting and it has not stopped, this is a safety issue! then in 2018 with only 32k miles or so I started to hear a squeal type noise at 2k rpm and about 60mph. It only happened a few times on the road trip then again on my next road trip. Honda looked at it and said they didn't know but the transmission fluid should be changed. It was changed at 29000 miles with the 30,000 mile maintenance. When it happened again on the freeway I took it in again, now at 47,000 miles. Honda says the transmission fluid is dirty and needs to have work done. 4 weeks later I am still waiting for local Honda to get ok from head Honda for fix of throttle control whine. Honda tech was able to hear the whine/squeal while driving it.