Duke University employees want a jury trial in their lawsuit challenging how the school runs its retirement plan.

The employees’ request, which comes two weeks after a federal judge certified their case as a 40,000-person class action, was spurred in part by Duke’s announcement that it would voluntarily overhaul its retirement plan by January 2019. The proposed changes, which include consolidating plan record keepers and eliminating 90 percent of the plans’ investment options, would address many of the employees’ complaints about the retirement plan and could render portions of the lawsuit moot.

In an April 23 motion, the employees clarify...