94gtcobra

I just installed the transgo shift kit which didnt make really a diffrence. Also the overdrive worked fine for about 1 hour and then after i went on the freeway and the od kicked in the overdrivegear would go neutral and i had toturn off the overdrive off. Today i drove it and it worked forlike to5 minues and then it just started to do the same thing again. What do you guys suggest is the problem, can it be because the fluid is to high, any other suggestion. PLEASE