Some models have a problem were the transmission won't shift into fourth gear intermittently. This problem can commonly be repaired with a software update from Honda.Google+
Car Problem Reports
Honda Ridgeline Software Update Will Fix Problem When Shifting into Fourth Gear
Honda Ridgeline Problem
Average Mileage: 73,100 mi (40,000 mi - 120,000 mi)
Visitor, 2006 Honda Ridgeline, 120,000 mi
Strange vibration for about a second when traveling at about 40mph.
Visitor, 2008 Honda Ridgeline, 89,000 mi
humming noise at 40-40mph before shifting into 4th gear
Visitor, 2006 Honda Ridgeline, 78,000 mi
Early shifting into 4th gear
Visitor, 2006 Honda Ridgeline, 40,000 mi
Got software update and no more issues.
Visitor, 2007 Honda Ridgeline, 50,000 mi
problem shifting into 4th gear at 40-45 mph
Between 40 and 45 mph the truck hesitates to shift to the next gear.
Visitor, 2007 Honda Ridgeline, 69,800 mi
Sometimes wont shift to fourth without further exceleration.Costing higher fuel use.