Hi, your temp prob is almost certainly thermostat sticking, when it gets very hot it forces it to get unstuck. Your shudder, it may very well be the beginning of a fault in the gearbox, on light throtle there is less pressure inside, and so the band/clutch is applied more gently, but when it is tired it might give you this shudder. Get it looked at BEFORE it gets worse as at the mo it might well adjust, if it is a band. Or you might be able to increse the presure a tad which might cure it. Excuse me if I am wrong its been some years since I did auto boxes. Tapping noise, are you sure its not the lifters? MarkS