Why aren't more people...

[CJim7]

Skipping on a D60 and going after D70's? The component difference between shaft diameter and R&P size is more than nominal. D70's are all 35 spline where as it takes a bunch of work and money to get a typical 60 up to that kind of strength. And clearance is almost the same between the 60 and the 70 center section....its tough to visually tell a D60 from a D70.
Strength gain and obvious clearance would definately make it a better option over a 14b.
That, and i have found them abundant. Ran across a srw D70 today for $300.

Side by side with the option, I think I would go with a D70....it sounds bigger and scarrier...but it really isnt. Just a big increase in strength.

 

[Tinman22]

Although Dana 70s do have a higher spline count , (although early dodge and i.h.c. 70s had 23 spline) larger dia. Shafts and tubes and some have a higher G.V.W. not all are better than a 60 . Early closed knuckle 70s had weak axles and 44 sized u-joints or even worse the dreaded and possibly poisionous (for those of us with allergies too shellfish) TRACTA joint no not "tractor" and no not available at your local parts store. Different pinion offsets 1/2,5/8,31/32 allowed for different gear ratios so make sure front ratio will work with rear ratio. Stud diameter and bolt pattern may also be an issue if the donor is a gmc kodiak.
Answering your question "why" I guess the answer would "easy" to find , build and modify . Pairs (front and rear) are common (i cant swing a dead cat around here without hitting one) for reasonable cost, usually with 4:10 or 4:56 gears stock and typically strong enough for most jeep applications. But if it will work and you can get it do it if for no other reason than being able to correct people when they say "nice Dana 60" . See it made ya smile already!

 

[Incommando]

I think that maybe the OP was discussing the D60 & D70 rears as the D70 front was an unusual bird. The later ones used under Kodiaks were an exception. All of the early axles like the closed knuckle 60/70's fronts and the low spline count rears sucked compared to those offered after the early '70's. Same with the Dana 44 front/rear. The two-piece axle 19 spline Dana 44 rear was not a good unit and the low-spline front was not either.

I agree that even the later D60 rear is over rated. The drawback to the D70 is that there are several versions and some aren't that much of an improvement, such as the D70 U that folks drool over just because it has a smooth underside. Some D70's are much stronger than a D60, though. Research the D70-HD for example. It is way stronger than a D60 or even the other other D70's. GM used them in heavy gvwr trucks ( such as the crew cab dually with the camper special package) where the dually 14-bolt didn't cut it and Ford did the same when the 10.5 Sterling wasn't enough. Not only do the D70-HD's have 4" tubes they also have thicker tube walls and larger spider gears and carrier bearings. It was eventually replaced by the D80, but the D80's diff. hangs even lower. If you can find a D70-HD that is about the pimp in a stock rear axle. I had a '79 Chero with a D60 front and D70-HD rear and, with only running 37's, I never worried about my axles.

 

[BajaEdition]

one large thing you have to look at is aftermarket support.

face it the D60 has support up the yangyang, the d70 does not

 

[Tinman22]

Yeah guess your right! Oops! I'll shut up now!