Whats the strength difference between the combos though? I have heard that the Ford 44 isnt much stronger
that a d30... not worth the swap. Is my source wrong?
I've been doing a lot of reading on the combo swap, and from all the sources I've gathered that the ford HP D44 is a bit stronger than the D30. a good strong axle to get is out of a 1973-1975 Ford F-100 which have the weld on wedges that can be cut off, the late 70's front ford D44 had the cast wedges and would require re tubing. the axle tubes are 2.75" with 0.5” thick walls and the 5-260 Cardan joint from 1971 to 1972 and changed to larger larger 5-297 Cardan joint from 1973 to 1975. the shafts are 1.31" 30 spline 8.5" ring gear. these axles are rated at continuous output torque of 1,100 ft/lbs and maximum output torque of 3,460 ft/lbs
as for the Dana 30, it has same Cardan joint 5-297, but the axle shafts are only 1.16" 27 spline with a 7.13" ring gear, the axle tubes are 2.5" with 0.25" thick walls. these axles are rated at continuous output torque of 640 ft/lbs and maximum output torque of 2,350 ft/lbs. The 5-297 Cardan joint yield strength is rated at 1,600 ft/lbs and ultimate tensile strength of 4,600 ft/lbs. the Cardan joints can be upgraded to a CTM, OX or Yukon which are said to be 2 - 3 times stronger.
to me the front HP D44 is quite a bit stronger, which changed my decision on building up my front D30 for my XJ. In my opinion it will cost only a little more to build up a Ford HP D44 than the D30.
It wouldn't really be necessary to truss the front D44 as it would the D30 due to the thick walls of the axle tubes.
the Rubicon D44 has the same size axles as the Ford D44 at 1.31" 30 spline 8.5" ring gear i'm just not sure on the axle tube diamiter and wall thickness
also here are some numbers for the axle size strengths.
this is an aproximate yield strength in ft/lbs
D30 minor spline diamiter is 1.11-inch 1040 carbon steel 2,371
1.18-inch 1040 carbon steel 2,835 5
1.18-inch 1050 carbon steel 3,939
1.18-inch 1541 carbon steel 4,424
1.18-inch 4340 alloy 5,665
1.34-inch 1040 carbon steel 4,174 8
1.34-inch 1050 carbon steel 5,738
1.34-inch 1541 carbon steel 6,446
1.34-inch 4340 alloy 8,254