89 Toyota Pickup Overdrive Problem

[mbmike]

Hello,

I have a 1989 Toyota pickup. The overdrive on the automatic transmission keeps turning on and off. I hear the relay clicking, but the light on the dash doesn't change. I tried replacing the relay, with no luck. Any ideas?

Thanks,
Mike

 

[jhnLennon]

try running the diagnostic for shift computer,there is a pin you have to jump to ground int he diagnostic connector by the relay box by the battery,cnant remeber what pin though,it is in the fsm you can donload on this site under the FAQ setion in this tech section we are on.does the overdrive light flash?you sure it is overdrive kicking out or the lock up torque converter?both are controlled by solonoids.if it is the solonoid it ill show a code in the diadnostic.some codes will cause the light to blick some wont.