This is where a sit down with a knowledgeable financial planner would be wise because there are too many variables to consider. Everyone's situation is different and you can never know what tax law changes will happen in the future.
Such as if you really want to take out $40K from the pension then 85% of your SS benefits will be taxable and every dollar you take out of the 401K or IRA is taxed. If you split up your deduction to a 401K and a ROTH 401K then you can take out some from each account and keep the taxable portion below the range where your SS benefits become taxed. And you have to consider the RMD you will need to take ... if your 401K grows a lot over the years then this could be costly as you will not have a choice on how much to take out. I have a couple of doctors who invested wisely and contributed the max allowed every year to the SEP IRA and now their RMD each year is actually more than they ever made when they were still working so they are actually paying taxes at a higher rate AND their SS benefits are 85% taxable as well.
