I know the DC-10-40 doesnt have that extra landing gear. I only just realised when I was copying the info from wikipedia.

Wikipedia

The first long-range version fitted with Pratt & Whitney JT9D engines. Originally designated DC-10-20, this model was renamed DC-10-40 after a special request from Northwest Orient Airlines: the aircraft was much improved compared to its original design, with a higher MTOW (on par with the Series 30) and with more powerful engines, and retains the increased wingspan from the DC-10-30. The airline's president wanted to advertise that he had the latest version.[32][33] The company also wanted its aircraft to be equipped with the same engines as its Boeing 747s for fleet commonality.[34]
Northwest Orient Airlines and Japan Airlines were the only airlines to order the Series 40, respectively ordering 22 and 20 aircraft. The Northwest DC-10-40s were delivered with improved engines, Pratt & Whitney JT9D-20 engines producing 50,000 lbf (222 kN) of thrust and a MTOW of 555,000 lb (251,815 kg). The DC-10-40s delivered to Japan Airlines were equipped with P&W JT9D-59A engines that produced a thrust of 53,000 lbf (235.8 kN) and a MTOW of 565,000 lb (256,350 kg).[35]
Forty-two DC-10-40s were built from 1973 to 1983.[36] Externally, the DC-10-40 can be distinguished from the DC-10-30 by a slight bulge near the front of the nacelle for the #2 (tail) engine.

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