Box 2a should be the taxable amount but check it. Code 3 in box 7 means it is a disability pension distribution. What makes it taxable or not taxable is where it was paid by the employer (taxable) or employee and whether pre-tax or after tax dollars. Check it to make sure. If taxable then your age determines where it is reported on 1040. Before minimum retirement age the then 1040 line 1h. After min. retirement age then 1040 5a and 5b.