I have a 401k worth about $45,500.00. I took a loan on my 401k for about $20,000 2 1/2 years ago. I have $11,500.00 to pay back on the loan. What would the penalties be if I closed my 401K and transferred it to another another 401k less the loan amount

First, how do you propose to "transfer it to another 401(k)"? Are you now working for a different company than the company where your 401(k) loan is located?

If you don't continue to pay off the loan you will owe income taxes (federal and state/local if applicable where you live) plus early withdrawal penalty on the outstanding amount of the loan. Figure, say, 20% for federal taxes, 10% penalty, plus 6% state incomre tax, and that means you will have to write checks for about $4100. You're much beter off just continuing to pay off the loan, and avoid all these taxes and penalties.