One test I've used is to drive about 20 mph in 2nd, I believe, and then floor the gas. If the engine RPM stays low and just climbs as the car accelerates, and doesn't "flare", the clutch is probably ok. Another test is to put the car into 2nd, rev up the engine when stopped and let out the clutch. A good clutch will grab hold and nearly stall the engine. A bad clutch will slip and engine speed will increase. Don't repeat this test without letting the clutch cool down, as it is hard on the clutch.

If you are having trouble shifting into low, check the clutch adjustment. On my 240s this has been a common problem. I'm not familiar with the 740 clutch which may be hydraulic. Try reading the FAQs.