Own a 2002 Infinity Q45 with approximately 250k miles.

We have been experiencing hard shifting between 1 and 2 gear for about 1 year but the hard shift have really gotten pretty bad this past week. Transmission fluid and filter were changed 3 months ago.

We decided to take the car to a transmission shop and they think that it might be a control module (part #31036AR160) but are not 100 percent sure. They also reported that the cars transmission is acting one way when its cold and a different way when its warm or hot.

They are not able to pick up any codes at all. No check engine light.
They believe the tranny is fine and that it must be some kind of electronic component.

One guy on a different forum says it might be worth checking out the transmission resistor.
Same guy sent me a PDF schematic but Im not able to find that resistor on the schematic.

I called the Infinity dealer and the sales guy never even heard of that.

Need help with this one.

Any advice is greatly appreciated