Oshkosh Truck Corp. posted profits of $6.1 million for its first fiscal quarter -- a 56% increase over $3.9 million in profits for first quarter fiscal 1999. Net sales for the quarter, which ended December 31, 1999, were $244 million versus $223 million a year ago.

The company said sales and income growth were led by the commercial segment, the largest of the company's three business segments. Combined sales for the segment were $115 million, up 19% from last year. The biggest came in concrete placement sales, up 18% and refuse sales, up 21%.