Originally Posted by ScottGem
As shunned indicated you should be talking to the benefits adminstrators at your company. The 20% withholding is just that, a withholding. Its NOT the extent of your tax liability, just like what's being withheld from your paycheck is not the exact amount you pay.
My question is have you explored a loan rather than a withdrawal? Mosy 401K plans have a load provision. The kicker is that the interest you pay goes right back into your account. Essentially you are borrowing from yourself and paying yourself interest. So instead of a penalty and a tax liability, you actually increase the value of your investment.