hi there wondering if anyone can give me some advice, i have EA 4speed auto, the problem is when i drive it sometimes slip down 1 even 2 gears then slips back to normal and on the highway it takes about 5 minutes of driving before it gets out of 3rd and into 4th, its eating the petrol real bad and i have to get it fixed, just wondering will a simple gearbox service fix it or should i just get a new box????

cheers