Inside Report (5)

There may be trouble brewing for US carmakers with plants north of the Canadian border.

Canadians represented by the United Automobile Workers say they don't intend to renegotiate auto contracts early and grant contract consessions. This breaks with the past, when contracts with US carmakers set the pattern for Canadian pacts. Canadian spokesman Douglas Glynn says, ''The situation up here is vastly different'' from down south. Auto labor costs are $5 an hour less than those in the US. And Canada's inflation rate is 12 percent, compared with 3.2 percent in the US.

Some advocates of national unions in Canada say the move could lead to an eventual split with UAW.