So I'm in the middle of my Cummins swap. I was planning on using the Dodge Dana 70 out of my donor truck in my '78 Crewcab 4x4. I occasionally haul a heavy camper with my EB on a trailer behind it.

So what are some opinions on rear axle choice? Stay with the Dana 70 or go with a Sterling 10.25 or 14 bolt?

Ryan

 

I would think the D70 is plenty heavy for your application... plus the ratio should be right for the Cummins. As long as it isn't too beat, I'd run the D70.

 

find a D70 from a Ford, it should be 35 spline; all the Dodge one's I've seen are 32 spline. the D70 has a much higher overall torque rating than the 14 bolt or but is comparable to sterling (sterling still has more reliability issues IMO, Dana axles don't ever really "fail"). the nicest thing about the sterling, is I believe it has the largest distance between the backing plates of the 3, so you have more room for springs (and bleeding brakes/changing wheel cylinders if you're into that). I know on the D70U in my F350 and the 14 bolt i swapped into my bronco, both have HUGE 12-13" drums that stick out from the wheel a good 2-3" per side, getting to the brake bleeders is difficult.

all 3 got the job done perfectly fine in big trucks for a lot of years.

 

Why not wait on the rear axle swap till after you drive it with the Cummins for a while?

As far as I'm aware the only thing that may need changed other than where the perches are is an adapter U-joint, don't believe there is enough of a pinion snout length difference on any of the axles to warrant needing a new drive line.

I've broken a LOT of automotive drive train parts and never killed a Dana 60, do you really need to upgrade? I know your camper and your trailer are both heavy so you may be doing it for the rating but at the end of the day the rating that would concern me would be your tires, not your axle.

 

I have 200K on a Dana 70 in my 2000 Dodge CTD, only problem I've had was a leaky pinion seal. Dont see why it would not work for you.

 

I could. But I need to regear. And the driveline needs to be modified. So I don't want to modify the driveline once then again when I switch out to the Dana 70.

I'm going to use the larger u-joint all around. Don't want to break any of the smaller ones. Plus the driveline forward of the carrier bearing needs to be modified for length.

The Dana 70 is already geared at 3.54, so I don't have to change those. The brakes are 13x2.5" whereas the Dana 60 is 12x2.5", so I get a little more braking surface.

 

What size U-joints are you going with?

When I did my ZF5 swap I changed to 1410 all the way through.

Was unaware of the brake size difference.

I currently have a factory disk D60 out of an E-250 and really like it, however, the one I have is the Semi-Float version with 3.73 and I will eventually change to the Full-Float version out of an E-350 with 3.54. This sucks as I had 2 of them sitting in my shop but due to finances I had to sell them, paid the rent though.

Seems you already made your choice as in your build thread you've moved the perches and started prepping the D70 for install. Is the WMS-WMS Track Width the same?

 

I am a big fan of the 14 bolt. I have a tuned up 12V Cummins in mine and I am in the process of putting in a factory disc 14 bolt. I friend of mine blew up his D70 in his Cummins. I have also watched people twist a pinion off at the yoke of a D70. The spline count where the yoke goes on is the same size as a D60.


Here is why I like the 14 bolt:
- 3rd pinion support inside of the ring gear that supports the pinion on both ends and it is not cantilevered
- the factory open carrier design is far superior in strength compared to the D70. The carrier has 4 spider gears vs. the D70s two spider gears. The 14 bolt carrier is in two halves that get sandwiched together so the casting does not have a huge hole in 1 or 2 sides that is needed to load the gears in other carriers.
- they are 30 spline axles but just as big as a D70s axles. Spline count means nothing...diameter does.
- why does almost every pulling truck use a 14 bolt? It is rare you will ever see a D70. I think that right there says a lot.

 

Here's why you swap out a D60 when you do a Cummins swap. I run a Sterling 10.5 now.



<a href="http://s742.photobucket.com/user/Fordworth/media/D60%20Destruction/2012-02-06_19-11-04_608.jpg.html" target="_blank"><img src="http://i742.photobucket.com/albums/xx65/Fordworth/D60%20Destruction/2012-02-06_19-11-04_608.jpg" border="0" alt=" photo 2012-02-06_19-11-04_608.jpg"/></a>

 

Yep. This is exactly what I have done with a D60 and a Ford 9". Busted the stock carrier housing at the thinnest portion where the pin goes through due to the huge open windows on both sides. Your stock D70 carrier has the same weak link. An aftermarket full carrier replacement locker would eliminate this issue however.

 

people run 14 bolts because they are dirt cheap with minimal parts variation over their production run.
having run both, I personally would take a D70, but i remember when i too was on the 14 bolt band wagon. comparing open carriers is pointless IMO, anyone serious runs a good posi or locker (of which there are much fewer options for the 14 bolt). show me a picture of a broken Dana open carrier and I can find just as many pictures of grenaded gov-locks lol.
check the rated torque loads for a D70 vs 14 bolt....don't even bring the D70 HD into the equation...
D70 35 spline shafts DO NOT neck down, 14 bolt shafts are like 1.4something at their smallest OD...
D70 has larger and thicker tubes that don't neck down like a 14 bolt....
D70 has more plug welds and a nodular housing vs cast on the 14 bolt... i've seen quite a few 14 bolts with spun tubes and plenty of trusses rip off the cast housings too. since the housings are cast, its not a great idea to weld the tubes to the housing either.
14 bolt is quite a bit heavier and has worse ground clearance.

about the only thing i honestly see going for the 14 bolt is that it is marginally easier to re-gear, at least if you are limited on tools. that being said...good luck finding a 3.55 ratio to match the OP's front diff for a 14 bolt dana always wins in terms of ratio options.

like i said before, all are plenty strong and all will get the job done. and all can be had for roughly the same price if you shop around and all have strengths and weaknesses. we could debate this in circle for days...its just like every other ford vs gm vs mopar debate...

or you could be a BIG MAN and step into the 11+" ring gear territory...with a Dana 80 or AAM axles

 

Thanks for all the replies. I've decided that I'll stick with the Dana 70. I tend to agree that all 3 have pros & cons. And there's plenty of Dana 70s out there behind turned up motors carrying campers & hauling trailers. I think I'm safe sticking with the Dana 70.

Ryan

 

Though you haul/pull quite a bit of weight you're not the type that beats on your truck, which is why I feel the D60 would have survived just fine.