I guarantee it is on you w2, you're just not looking in the right place. the 401(k) goes in box 12, with a "D" to indicate that it's a 401(k). The 403(b) has its own letter code.
I'm assuming your 401(k) and 403(b) are from different employers. The maximum you can contribute to these combined is $17,000 this year. If the money is already there, you need to have some of it withdrawn by April 15th to get you down to $17,000, or you will end up paying tax on the excess both this year, and when you take it out (as well as on the earning attributed to the excess). I would do this as soon as possible.
Nice plan, but you have to be careful when 2 employers are involved, because they don't know to keep you from making excess contributions.