Dana 70 vs 80 vs Model Year identification?

[ENafziger]

I've got a '91. 5 W250 Cummins. The Getrag is going out, and I'm doing a NV4500 conversion. In the process, I'd like to soon do a Dana 80 swap for the rear, but I'm getting conflicting info.

Did the 1994 - early 1998 Dodge 2500s come with both Dana 70s and Dana 80s?
If so, how do you easily tell the difference?

I found a 1995 Cummins 2500 that a guy is parting out. It's a 4x4 with an NV4500 and 3. 55 gears. I'd like to buy the rear end from him, but he says (uncertainly) that it's a Dana 70. I thought when Dodge switched to the P-Pump engines that they also swapped to the NV4500s and Dana 80s?

--Eric

 

[ENafziger]

I've found this: http://www.dodgeram.org/tech/specs/axle/rear_axle.html

And I've also read that all '94 - '98 Cummins with autos got the Dana 70, and all with manuals got the Dana 80. Can someone confirm? If so, are these the "real" Dana 80, or the Hybrid?

 

[Bob4x4]

All manual trans trucks 94-02 hybrid Dana 80 as well as all dualies
All auto non dualies are 70's

 

[NIsaacs]

What Bob said, also for quick visual ID, the 70 has 3. 5" axle tubes, the 80 has 4".

Nick

 

[RustyJC]

See HERE.



Rusty

 

[ENafziger]

Thanks guys. So it looks like the '95 Model 2500 I'm looking at has the Dana 80 hybrid, since the truck also has the nv4500.

Does the "hybrid" part mean it's a real Dana 80 center section (11" ring gear and 1. 5" 35 spline axles) with the smaller Dana 70 axle tubes?

Is it worth the trouble to swap the stock Dana 70 for a Dana 80 hybrid?

 

[NIsaacs]

Is it worth the trouble to swap the stock Dana 70 for a Dana 80 hybrid?

Yes... . the 80 hybrid is only smaller than the standard 80 at the spindle and hub, the rest is the same.



Nick

 

[ata]

If it still has the DATA plate on the Diff. cover that will tell you what it is. Second on the axle tubes between the spring pad and the brake backing plate you will see where the axle tube goes from 4 inch to 3 1/2 inches.

 

[JR]

They should be stamped either 70 or 80 on the bottom of the housing towards the left side of the pinion housing. My former 00 2500 with an auto had an 80 rear. I always assumed it was a 70 until I had to replace the pinion seal and an axle seal. I didnt know enough of the trucks prior history to know if someone had swapped the axle out or if it was ordered that way.

 

[Shadrach]

We put an 80 in my buddies 93 W350 dually because he broke pinion teeth in the 70 twice With a stock 91. 5 I don't think you will need one. He has a tweaked 96 engine ( and G56 trans ) in his truck and is a heavy beast as it is a service truck. Shad

 

[ENafziger]

We put an 80 in my buddies 93 W350 dually because he broke pinion teeth in the 70 twice #ad
With a stock 91. 5 I don't think you will need one. He has a tweaked 96 engine ( and G56 trans ) in his truck and is a heavy beast as it is a service truck. Shad

I have 4" straight exhaust, M2 fuel pin, pump to the head, "power" screw all the way in, full throttle travel, 366 spring, Raptor 150 lift pump, HE351CW turbo, Diesel Power exhaust manifold, 5 x 14 injectors, etc. I know that's not extreme, but it is considerably more than stock. I just upgraded to 9/16 lug studs and 19. 5 wheels and running 35" tall tires, and am in the process of installing a NV4500 transmission. I have a an HX55 turbo I plan on putting on under the HE351, and propane injection that I'm in the process of completing as well. Again, not extreme, but I'd say 400 - 440 hp is realistic.

Will the 70 hold up fine under this? It's mostly a daily driver, but does pull up to 22,000 occasionally.

--Eric

 

[Shadrach]

His problem is the constant weight, 15k # all the time, and sometimes he pulls a a pick up box trailer loaded with scrap metal. Although I can't say for sure but I think you should be OK as lots of others have pulled that kind of weight with no broken diffs. My buddy seem to be able to break anything Shad

"The biggest problem with most truck is the nut hold the wheel "

 

[AClayton]

I am currently in the process of replacing my 70 with an 80. The 70 lacks pinion support when towing heavy and coupled with high hp; according to many mechanics on here.

 

[Bob4x4]

Eric, look at it this way-the factory went to the 80 with just 175hp in front of the nv4500

 

[DVolk]

I think it all depends on how there driven and main ained and the lube used in the rear ends . There is guys running ford 9" in cummins pwerd drag trucks as well as dana 60s , so go figure

 

[NIsaacs]

I think it all depends on how there driven and main ained and the lube used in the rear ends . There is guys running ford 9" in cummins pwerd drag trucks as well as dana 60s , so go figure

Just for reference, I think Dana rates the 70 @ 2,000 lbs trq continuous to the ground and 8,000 intermittent. The 80 is 2,500 and 10,000.



Nick

 

[Bob4x4]

I think it all depends on how there driven and main ained and the lube used in the rear ends . There is guys running ford 9" in cummins pwerd drag trucks as well as dana 60s , so go figure

Those 9'' rear ends are so far from a stock 9 and will cost way more than an 80 :-laf

 

[RSchwarzli]

I would say go 80 at this point if you are already in there.....

 

[ENafziger]

The only thing making me a little hesitant, is that I just put so much time into the D70, upgrading the hubs to accept 9/16" lugs, etc. Can I re-use my same D70 drums and hubs on the D80 hybrid?

 

[DVolk]

For the price id buy all the gears from Randys Ring & Pinion and just rebuild it , i done mine and it works fine