What are the differences between the 73-75, 76-77 and, 78-79 Dana 44 HDs

I'm trying to get disk brakes on my 75 and I found a 76 and 78 axle both for a lot

I assume it will just drop in but I don't know for sure

 

I personally would choose the 76. I am not too familiar with the older ones, but I think they were drum, but 76-77 have the thickest axle tubes, and 78-79 has a better steering set up. The 78-79 has a weird sleeve setup on the tubes where the wedges are, but the 76-77 is a solid tube, like you would expect a solid axle to be.
When I did my 4wd conversion, I used a 77 because of the tubes, and made my own 78-79 style steering using chevy tie rod ends and DOM tube.
This article is pretty good for covering dana 44 info:
Dana 44 Solid Front Axle: Reverse Spiral and Standard Housing info..

 

This is for the standard D44's.

The D44HD will be 8 lug and from a F250. And mounts by leaf springs.

75 and earlier was low pinion closed knuckle drum. The 76 will be low pinion open knuckle disk. Then midyear 77 went to high pinion open knuckle disk. All same tube thicknesses. I measure the spring mounting widths are off by like 1/4 inch from the midyear 77's. Hardly noticeable after you ratchet the springs over to fit. Bushings might wear prematurely? The 76-77 1/2 will have a higher steering arm than the 78+. Rest is all the same.

 

Any benefit to the 78 (bigger brakes, stronger parts, etc.) or is 76 just the way to go

 

Unless I am mistaken the brakes should be the same only difference would be single piston vs dual piston, don't forget to change your master as the 75 is set up for drum/drum and would have a residual pressure valve for both the front and rear where as the master for a 76 and up is set up for disc/drum and would have no residual pressure valve for the front.

 

I think the general consensus is that the high pinion 44's are better/stronger than the earlier 44HD's (even though the hubs are physically smaller). Brakes should be the same.

 

Strength is virtually identical between the hp and the lp it boils down to what one you can find and how much work you want to do the 76 is a bolt in short of the master the 78/9 requires reworking the steering set up.

 

This is what I was referring to (thanks to Montana Highboy I don't have to type it out):

Besides the obvious increase in ground clearance and better drive shaft angle the HP gears are cut in reverse allowing the pinion to turn the ring gear from above its center axis as opposed to below its center axis like a LP axle, it's "pushing" the gears as opposed to "pulling" them making it stronger, when you put a low pinion in the front, the ring and pinion teeth are loaded on the weak side, with a high pinion in the front they're loaded on the strong side, a HP front axle is making contact on the stronger drive side (convex) of the gear tooth as opposed to the relatively weaker coast side (concave) of the gear tooth.

 

kind of a mute point when you consider how often the typical person spends in 4x4

 

Is it really single piston calipers I'm pretty sure I remember it being 2 piston

 

There was two different styles some had dual piston some had single piston

 

Not really, the op asked if there were any benefits to going with a 78 (hp 44) front axle & I just listed three (i.e. stronger, better ground clearance, & a better ds angle).

 

F100/F150 1/2 ton 2wd & 4wd with disk brakes had single piston brake caliper, F250/F350 3/4 ton, 1ton 2wd & 4wd with disk brakes has duel piston brake calipers.

 

I'm confused.. my 73 F100 has a high pinion drum D44. Where does that fit into these configurations?

 

It's 1/2 ton we're talking 3/4 ton