I've noticed my overdrive kicks in way to early at about 50mph on quarter throttle. Then it wont kick out of overdrive until I practically floor it even if I'm going uphill at 1000 RPM. It will only downshift once I've slowed down. I do have a tune on it but it was doing this before I loaded it. Is this normal or is there a solenoid that may be malfunctioning that I can replace easily?