What would cause my transmission to not shift into 2nd and then not shift at all

Check the transmission oil level after that, servicing the transmission may be the first and cheapest place to start. In servicing the transmission the condition of the oil will be checked, the oil can be checked for debris, the filter and magnets at the bottom of the oil pan can be inspected, and on a test drive afterward the shifting of the transmission can be checked to see if the transmission may have further mechanical or electrical problems.