First, you may have already violated the one rollover per year rule, if you did the transition from the 40l(k) to the IRA within the past 12 months — and now are hoping to do another! So when did you do that original rollover?? The second withdrawal for your “loan” may be considered a taxable distribution if the two transactions were made within 12 months of each other!
Here’s what the IRS says about this issue:
IRA one-rollover-per-year rule
You generally cannot make more than one rollover from the same IRA within a 1-year period. You also cannot make a rollover during this 1-year period from the IRA to which the distribution was rolled over.
Read more here.
And if you do qualify because the initial rollover was more than a year ago, I would DEFINITELY put the entire amount back into the first IRA. You are just asking for trouble from the IRS and custodians if you divide it into two new IRAs. I’m not sure how they will look at it in the end — but they WILL look at it, for sure!!!