traditional IRA using funds from my pension

we have to assume the distributions from your pension are RMDS. Otherwise it would make no sense to take distributions from your pension which are not required in order to put money in your spouse's IRA. that would in effect be a wash for income tax purpose's. however, if it is an RMD then the rules state if your spouse has earned income, even if you don't, you can make an IRA contribution for her subject to the limitations for that year.

there are other rules. the contribution limit, provided a joint return is filed, the lower earning spouse can consider the other's compensation to the extent it has not been taken into account in making an IRA contribution for the higher earning spouse.

since you are covered by an employer retirement plan, I assume your spouse isn't, the amount available for you to contribute based on your spouse's earned income is subject to phase-out based on modified agi on the joint return.  

Q. Can I contribute to my traditional IRA using funds from my pension if I am retired and not currently employed?

A. It depends on what you mean by "using".  

Yes, you may use that money (or any other money) to fund your IRA.

No, you may not use that income to qualify for an IRS contribution. It is not "compensation".  But as others have said, you may count your spouse's earned income (compensation) to qualify for an IRA contribution to your IRA. Doing this is sometimes call a "spousal IRA".  But, you may not double dip. For example; your spouse has $10,000 of earned income and makes a $6000 contribution to her own IRA.  That means you are limited to only a $4000 IRA contribution.