Union says offer did nothing to provide job security during the term of the agreement.
Even as talks continue, the company is leery of settling the strike and saddling itself with costs that it will have to pay later.
Workers howled and GM received withering criticism from politicians and on social media about cutting off the benefits.
Minor issues largely are resolved, focus shifts to wages, use of temporary workers and other contentious issues.
The union wants a bigger share of GM’s more than US$30 billion in profits during the past five years.
Follows the full shutdown of vehicle production at the company’s Oshawa Assembly Plant.
On Friday, GM halted production on its flex line in Oshawa that produces the Chevrolet Impala and Cadillac XTS and employs about 650 workers.
In August, FBI raided the suburban Detroit home of UAW President Gary Jones as part of the widening federal investigation.
Unifor president cites plant cutbacks and closures on both sides of the border following pledges to maintain operations.
33 manufacturing plants down in nine states across the US, plus 22 parts distribution warehouses.
But it doesn’t mean there will be a work stoppage. Contracts expire Sept. 14.
It’s increasing capacity, improving operating efficiencies and making other upgrades at US plants.
Would have to repair more than 6 million trucks and SUVs at a cost of US$1.2 billion.
Workhorse Group would build a commercial electric pickup truck if it buys the facility.
The transition will cost $170 million and save 300 of the 2,600 union jobs.