The U.S. Postal Service is looking for outside help to find ways its pension system can save money by bringing it in line with retirement benefits offered by major private-sector companies.

The effort, reflected in requests posted on FedBizOpps.gov, comes amid wrangling between Congress and the mail service over how retirement benefits are funded.

The service is required to pre-fund retiree health benefits to the tune of $5.4 billion to $5.8 billion annually for 10 years ending in 2016. The payments were intended by Congress to fully fund retiree health benefits for 75 years. The Postal Service and its supporters have argued that the payments are dragging it toward insolvency, accounting for all but $9 billion of a $41 billion deficit.