During this time Daimler-Benz also restructured its model designations. The Mercedes-Benz Unimog models U 600/L, U 800/L, U 900 and U 1100/L had meanwhile been given their classic, rounded form.

The new, angular shape characterised the Unimog models U 1000, U 1300/L, U 1500 and the flagship U 1700/L with its 124 kW (168 hp) engine. The letter L stood for a variant with a long wheelbase, as most models were now available in two different wheelbases.

While the Unimog with the rounded cab constituted the lightweight series, the new series with the angular cab were divided into the medium-heavy and heavy-duty series according to their gross vehicle weight, and some engines were used in both - it was not easy to understand the model designation system. And last not least, the stalwart Unimog S still remained in the range as the only petrol-engine model, though its sales volume was declining significantly.

Clearly more easily understandable were the technical highlights: with the exception of the bottom-of-the-range model, all Mercedes-Benz Unimogs were fitted with disc brakes all round at the time the new model designations were introduced – long before this safety equipment became state of the art in trucks. The efforts of the Unimog people to give every customer the model he or she needed paid off in the form of another record figure: in 1977, the 200,000th Unimog was produced.