P Kennedy

Each manufactuerer will send a spec requirement to the component manufacturer. The Dana 80 "hybrid" is DC engineerings update spec requirement to combat hi torque 70 rearend failures and updated power in newer models. Most Dana axles are a "hybrid" ie; 44F's for Ford, Chev and Dodge will have different "pumpkin" orientations, lengths, tube diameters and spline numbers. Dana 70 rears also will vary in the same manner with the consistancy being ring gear size as per model number. Dodge will have the only true listings of what was supplied by model and serial number with basic general specs as per required on a chassis. First gen trucks were all built with HD60F's in the front and 70 rears, second gen were basically HD60F's in the front with 70's in the rear with automatics and 80's in the manuals but some 3500's had 80's either way. 3.0-3.9 ratios are one internal carrier and 4.0+ are another to accommadate the the ring gears and there high angle bevels in the teeth. IFS front ends are also "hybrids" without axle tubes and frame mounting case castings for mounting but will contain ring and pinion of the same dimensions within a series. PK