Unifor says it is entering a crucial stage of negotiations with Stellantis.
It's meeting with senior company executives on Thursday and Friday as talks continue ahead of a strike deadline set for 11:59 p.m. on Sunday.
Union officials are seeking greater clarity on product planning for the Windsor Assembly Plant, the Brampton Assembly Plant, and the Etobicoke Casting Plant.
"Unifor requested updated information about the forecasted re-tool timeline, product allocation, timing for product launch, projected staffing levels, and shift configuration," said an update on Unifor's website.
Unifor has already ratified agreements with Ford and General Motors.
The union said the focus now is on issues specific to Stellantis, including extending bargaining rights to future workers at the NextStar Battery Plant in Windsor and protections against outsourcing at parts distribution centres.
There's also work to do on the issue of pensions and protecting employment levels in the fire/security and office, clerical, and engineering units.
Unifor represents about 8,200 workers at Stellantis operations across Canada.
On Wednesday night, the United Auto Workers reached a tentative deal with Ford.
Workers at automotive facilities have been on the picket line for 42 days, and the UAW continues talks with Stellantis and General Motors.