It isn't " the system". So much as the " Republican led system".

Anyone with a pension is having to fight to keep it. ( except lawmakers). Consider non-federal government employees ( like city workers, teachers and others), union members.
Even some federal employees like Postal Workers.

Anything the R's can privatize, to make a buck off public money, they will. Including Social Security and Medicare.

I thought that the Teamster's pension fund was run by the union itself.

While their are many Republican sins to denounce, this case would seem to be more likely caused by poor fiduciary responsibility on the part of the union.

The U.S. Department of Labor has managed the Teamsters' Central States Pension Fund for investment purposes since 1982. The fund surrendered control years ago due to mob corruption that had influenced top fund managers and union leaders.