Tractomotive manufactured loaders for the G-suffix crawler tractor until Allis-Chalmers bought them out in 1959. The various G-suffix tractors were modified to varying degrees for crawler loader applications, the HD16G and HD20G most of all with bulbous hoods that rose up from the operator’s station to the radiator. Allis-Chalmers continued the model series that was in production at the time of the Tractomotive purchase. In 1959, the HD6G was redesigned with a hood that sloped down to the bucket. Only two crawler loaders, the HD7G and HD12G, were built without corresponding crawler tractor models, although the HD12G was about the size of an HD11 and used the same ripper. Because of the extent of modifications to the tractors, all Allis-Chalmers/Tractomotive crawler loaders models HD5G and up are classified as Class 2640, integral crawler loaders, even though technically the majority of models were not integral loaders in the truest sense of the term. However, the loaders built by the Industrial Tractor Division (655, H3, H4, HD3 and HD4) are considered to be attachments, because they truly were attachments for crawler tractors that had not been extensively modified. Other attachments, such as scarifiers, that were designed only for use with the loader arrangement of these tractors are classified loader attachments.