mind of its own gear change

hi there, i have a 2.7 mistral auto 1994.
with over drive turned OFF it runs like a dream but when you turn it on it changes from third to fourth and higher at WILL and will gladly change back in to third at over 55 mph (not very nice for any motor)if i play with the power/hold button it some times changes up again, as if i press the over drive button it will do the same but it rearly behaves.ANY info on this would be very much welcomed as i am pickeled to the fault,thanks phil.

[lacroupade]

Originally Posted by phil armstrong

hi there, i have a 2.7 mistral auto 1994.
with over drive turned OFF it runs like a dream but when you turn it on it changes from third to fourth and higher at WILL and will gladly change back in to third at over 55 mph (not very nice for any motor)if i play with the power/hold button it some times changes up again, as if i press the over drive button it will do the same but it rearly behaves.ANY info on this would be very much welcomed as i am pickeled to the fault,thanks phil.

hopefully its an electrical or sensor fault, but I haven't seen much experience on here of that kind of thing. the auto box on my wifes 99-plate T2 went hree years ago and cost me £1500 for a rebuild.....i suspect if you can't fnd a simple fix its more than the trucks worth to mend it and they are like hens teeth to find as I know to my cost....good luck though

chears mate,take care.