Ran fine changed transmission filter now it has no spark

Please explain this part better?

" it has no spark no power to coil unless the negative battery terminal is off"

The Medic

I got a test light from Napa attached it to the plug going to the coil on the hot side cannot remember the color of wire. No power to coil with key in the on position no power with key while cranking the engine over with the test light still in I took the negative battery lead off and boom coil as constant power put negative lead back on no power to coil.

So with the battery disconnected there is power at the coil?

With the negative lead off yes

So electrical power is present with no electrical source? That's a first for me my friend, let me know if you ever find out whats wrong.

The positive lead is still on the battery

But besides that.. Changed the tranny filter Now it has no power to coil any ideas

The only way you can make a circuit is to have a battery in line with the battery terminal off as ken says this just wont happen, however.... if the ignition is on and you make an earth through the test light, you will get a circuit but the globe will act as a resistance, some test lights are LED and will have a green and red light, depending on how they are hooked up an earth path will show with one light and power path will show with the other, can you give some more info on what you are testing with, because i am somewhat confused as well as to what you are doing to get the results you report.

one thing I forgot check fuses under hood and automatic shutdown relay they should be marked on cover for location