Pontiac Problems? Ask a Mechanic for Answers ASAP
You could backprobe the wire going into the transmission but this would be as accurate of a test you would rather do it directly from the solenoid harness. You will need to buy a voltmeter to do this test, here is a wire diagram let me know if you have questions, thanks.
Not good news first step is getting codes checked, it sounds like your converter needs to be replaced or your internal transmission clutch is burned up but you could try to replace the solenoid first if no help replace the tourqe convertor. Let me know if you have questions, thanks.