When I get up to about 45 MPH, in either 3rd or 4th gear, the torque converter will eventually lock like it's supposed to. But once it locks up, when I give it light throttle the car feels like it's bucking or wobbling slightly back and forth. If I hit the throttle enough to unlock the torque converter, or let off the throttle completely, the bucking goes away.
The check engine light has not come on yet and otherwise it runs well. I reset the computer with a cheapie OBDII tool, but that didn't help.
It's the wife's car-- I have somewhat of a mechanics background and I'm sensitive to every little thing, but she doesn't feel it.
I can't tell if it's a transmission or solenoid issue waiting to happen, or if it's just getting its "personality." That is, perhaps once the driveline is fully engaged it is sending some kind of harmonic vibration through the motor mounts. I've never had a car act like this before, though.
Being brand new I'm obviously going to have the dealership look at it this weekend but I was wondering has anyone else experienced this? Any ideas as to what I should tell the dealer to look for? Sometimes they need to be helped along...