I knew this was going to happen; Honda decided to "re-engineer" the transmission for the 2018 Honda Odyssey, and it's going to be a HUGE HEADACHE for the company in the near future.. and even bigger for owners!
I have owned a 2007, 2011, 2014, and now, a 2018 Honda Odyssey. I drive an average of 400 miles per day, 90% Highway, in the North Carolina Piedmont area. Loved my 2014 for the most part. Put over 300k miles on it before trading, and never had any major mechanical issue.
From the very beginning, I was not happy with the 2018. The transmission acted like it never new what gear to go into, and I was getting worse fuel mileage than the 2014 model. I started noticing noise from the drive train early on. If I eased off the gas, while slowing down in traffic, or approaching a stop light, and then re-accelerated, many times the transmission would hesitate, and then "bang" into gear, making a metal-on-metal noise.
At first, it was not very loud, and just slightly noticeable, but as time went by and I put more mile on the car, it became louder and much more noticeable! I took it to Autopark Honda in Cary several times with this complaint.. and I would always get the "We can't replicate the problem" response.
The last time I took it in, the car had about 58,000 miles on it and the drive train warranty soon to expire. That time, the mechanic acknowledged that the was definitely an issue, and had communicated with Honda Tech, but no resolution offered! I was told that they would "stand behind the car", should something happen.
Well, something happened.. the transmission failed. The first call from a Service Advisor told me the repair would cost almost $6,200 ! But then added that they would submit a claim to Honda Goodwill. The next day, I was informed that Honda would pay all but $1261 (which must be their actual hardware cost), of the repair.
I find this unacceptable! While I appreciate that they are willing to pay a large part of the cost; a Honda transmission should not fail at 75,000 miles.. period! Honda stupidly decided to re-engineer a perfectly good transmission, and came up with a dud.
I am also sure that my situation will not be an isolated one. During my 58,000 mile visit, I was given a 2019 Odyssey as a loaner for a few days. It made the very same noise!
So if you own a 2018 or newer Odyssey... beware! And make certain that you are having the transmission fluid serviced every 30k miles, or you will no doubt be denied any help when (no if), your transmission fails.