Doesn't happen to be City of Phoenix, does it?  Occasionally I see a funky 1099-R from them, but the client provides enough facts to verify it's taxable.  The Code 2 might indicate that this was a disability retirement, and some of these public-safety retirement systems are considered equivalent to workers compensation for disabled retirees, at least until they reach age 65.  

Have you contacted the payer's HR department to ask?  

I used to see some of these "zero Box 2" 1099-R forms from union pension plans also, and considered them fully taxable.  But then, I once saw a 1099-MISC for a union pension instead of a 1099-R, and all the retirees received proposed assessment of SE tax from IRS.