You will have to pay income tax , on the outstanding balance. Plus a 10% penalty if under 59 and a half! They are not deducted from your 401k but they will be due when you file income tax
This is the right answer. The loan will be treated as a withdrawal and as such will be taxed as ordinary income. They will also tack on a 10% penalty, which you pay along with your taxes.
You can repay with your own funds; however, you must repay the entire balance in a lump sum----no payment plans allowed. Payment of a partial amount now could reduce the amount that you would have to pay taxes on later.
There are no ways around the penalties.
This is from the Prudential website:
You must repay the loan in full within 90 days after termination or it will be considered a taxable event, subject to all current taxes and any early withdrawal penalties.
You can call 1-800-537-0189 but I am afraid that they will tell you the same thing that I just did. (They might use bigger words but the message will be the same)
You may want to Google "IRS Payment Plan".