Wont stay in overdrive!
 

Hi guys,
I have an 88 300zx turbo with an automatic transmission...i know...why havn't i swapt it for a 5 speed right! All I can say is married with children!!! Dont have a lot of time for my toys right now! Anyways it has been running relativly well for seversl years now but last week the overdrive started malfuctioning. When i accelerate from a stop it acts normal until it hits overdrive. It will go into overdrive as i let off the accelorator but if i try to give it any amount of gas it immediatly shifts out of O.D. which means i am stuck driving 60mph with revs in the low 3's. The O.D. button appears to be operating correctly as i have disengaged the over drive via the button to keep the transmission from constantly shifting in and out of O.D. given this recent issue. The light on the button doesnt work but i dont think it ever has but again the button functions as it should its just that the transmission will not stay in overdrive. So i can accelerate and then let off the gas and hit the button and it will kick into O.D. and coast down hills and on flats pretty well but as soon as i hit the accelerator just to maintain speed it kicks out of O.D.

Any ideas where to start. Could it be the O.D. solenoid or something with the computer or transmission itself? Any ideas would be greatly appreciated. If you think its the solenoid do you know where to find one. Orielly only sold the whole set for $350 which is not worth it just for one solenoid.

Thanks again for your help!

DJ