No shifting into OD

I just bought a 1988 Dakota 3.9 v6 and it has push button over drive. I know the engine has been replaced and I am trying to determine it they put a 3 speed auto with over drive in the truck or not. Is there any way to find out if the engine in it now has over drive or not? If it does any ideas as to why it will not kicked into overdrive?:banghead:

the engine change has nothing to do with OD. can you take pictures of the tranny if so I could tell you if the swapped. I would look for the electrical connector on the trans if it plugged in you should have a OD trans if not they probably switched it over to a 3 spd.

I changed the trans gasket and filter and did notice an extra connector by the pan that was not plugged in. I could not find any where on it to plug it in. If they chaged it to a three speed what would it cost me to get a trans with over drive.