I don't know your company's procedure and I don't know what they will send. I don't think you need an 8606. Here is my thinking:
When you made contributions to your 401k that were over the limit, you must have noticed your paycheck looked different at the end of the year because you had to pay tax on the excess contributions. In your 401k, you have pre-taxed dollars for most of it and already taxed dollars for the rest. The pre-tax dollars are easy and they roll into the traditional IRA. It is being rolled into a traditional IRA so usually we see code G.
The already taxed dollars form the basis of your 401k. Those were dollars that were not deductible, you paid taxes on them. The basis of your 401k is what is being rolled into a ROTH. If all of the 401k money were rolled into the traditional IRA, then your after tax dollars would be your non-deductible IRA portion that goes on 8606. That is the portion that rolls tax free into the ROTH.
The 8606 is if you have a basis in a traditional IRA. If all of your basis was rolled into ROTH, then you have no 8606 to fill out.
There are many options for what they could mark this but to show it is already taxed dollars being transferred, they need to pick a code. I have no idea what they will pick. When you look at the chart with the possibilities, they will decide. You can see the option with table 1 here. I used "probably" because it does get used but there are certainly a table full of options!
Once you have both forms, then we can help you get them entered and make sure your tax forms are correct.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
