40 ILCS 5/17-151
All pensions, annuities, refunds, or death benefits granted under the provisions of this Article are exempt from State and municipal taxes and are exempt from attachment or garnishment process. They shall not be seized or levied upon by virtue of any judgment or any process or proceedings issued out of or by any court for the payment or satisfaction in whole or in part of any debt, claim, damage, demand or judgment.
No pensioner has the right to transfer or assign his pension or any part thereof by way of mortgage or otherwise except for the purpose (1) of establishing and maintaining membership in nonprofit group health or hospital plans approved by the Board and (2) of establishing a living trust, the trustee of which is authorized to engage in the trust business, provided all pension payments so assigned are required to be paid monthly to the trustor or, in the event of his incapacity, expended for his benefit. The Board is hereby authorized to administer all the details involved in establishing and maintaining membership in such health or hospital plans for the benefit of the annuitants, but it shall not be obligated to do so or to continue doing so, if in its judgment such continuance is not desirable.
40 ILCS 5/17-151