Honda Odyssey 2005 with vibration/growl at cruising speeds. My Odyssey has a vibration/ growl when at crusing speeds. Under exceleration it appears to be fine but once you reach crusing speed (especially when the ECO light is on) it makes the noise and the vibration can be felt in the car. A tap of the accelerator will sometimes make it go away.

If this problem only happens when the eco light is on, then you prob have a bad rear engine mount. these vans have active front and rear engine mounts. when the engine is in VCM mode(operating on 3cyl) the front and rear engine mounts control the engine vibrations. when the rear one goes bad it connot control the engine vibrations. the rear mount can be visually inspected for failure(if its resting on itself), or on a test drive with the active noise control turned off. or engine brake torquing.

It sounds like the torque converter clutch is slipping. Deterioated transmission fluid can cause a shift quality concern like this. The first thing that needs to be done is to get that old fluid out of there. Check the fluid condition. It's probably dark brown or black. it should be bright Red. There is a drain plug on the bottom of the trans. Do a series of three drain and fills. (You'll need about 10 Qts of ATF-Z1 Honda fluid only.) Start by draining the fluid through a paint strainer filter. If the fluid is contaminated with clutch material. The trans will need to be replaced, but flush the fluid anyway. Fill the trans through the 17mm fill hole on the top of the transmission. it will take about three quarts. Then drive the car through all the gears to get the fluid curculating. Then drain and fill again. do this procedure two more times. and see if the the lock-up shudder is better or completly gone. This will buy you some time to save up money for a new trans and/or torque converter. 07-10 Odyssey's has a PCM update for this concern and if the update doesn't fix the shudder than the tourque converter is replaced. -hope this helps, best of luck.