automatic transmission

It's really hard to tell without inspecting the vehicle, and possibly performing a service and seeing if that addresses the problem you are having. It's best to have an experienced Honda technician look at this, with enough experience they may be able to tell you what the problem is based on past experience.

Check the transmission fluid level. The dip stick is removed and the transmission oil level is checked with the engine switched off (unlike many other cars). Honda suggest using Honda ATF-Z1 fluid in their transmissions. If the transmission oil hasn't been changed in the last 30,000 miles I would certainly change the oil. On this transmission it is a simple drain and refill it does not have a removable oil pan on the transmission.