My Pilot often shudders at 40 - 45 mph; if I back off the accelerator it stops and if I accelerate past 45 it doesn’t return. A transmission shop says it is not the transmission . Is there reason to be concerned , or is it just a querk of this vehicle?
Have your wheel balance checked first! That’s usually where the problem is.
Does it feel like you’re driving on those rumble strips at the edge of some roads? If so, my first guess is a failing torque converter. Honda and Acura had issues with that in the mid-2000s, although by 2009 I thought a lot of that was addressed.
It does feel like rumble strips when it is happening, although if I keep it in 3rd gear there are no rumbles.
Is a bad Torque converter dangerous?
Try adding this to the transmission fluid, and see if the shudder goes away.
No, but it may get worse until the torque converter clutch won’t lock up. Then it will probably turn on the check engine light (happened to my Civic).