Knowing your transmission’s hydraulic circuit — and solenoid circuits in particular — can be very helpful when identifying the underlying cause.
You may be familiar with a transmission called the JF506E, which in the North American market can be found in the VW Jetta, Golf and GTI; the Mazda 6 and MPV; the Jaguar X Type; and the Land Rover Freelander. It is manufactured by Japanese Automatic Transmission Co. (JATCO). In Europe the JF506E is in vehicles such as the VW Golf and Sharan, the Land Rover Freelander, the Jaguar X Type and the Ford Mondeo, to name a few. And the company said something to this effect: “You build the car and we will make this transmission fit it. The transmission will be versatile enough to accept programming of the computer to meet various strategies desired by the car manufacturer using the transmission.”