The manufacturing sector is suddenly flexing its muscles. The government Friday said orders for durable goods rose 3.4% in March, led by the transportation sector, and revised its February assessment sharply higher to a gain of 3.8%. Economists were forecasting a 0.7% gain in what is considered something of a difficult number to predict and an erratic economic indicator. Shipments rose 3.2% in March and are now up in six of the past seven months. Inventories edged up 0.1% after a 0.4% increase in February. Non-defense orders rose 2.1%, while defense orders fell 0.5%. Civilian airplane orders jumped 11.7% and orders for motor vehicles increased 3.6%. February's original reading was 2.5%.