I recently bought an 88 f350 that has a dana 70 under it. Is there an easy way to tell if it's an HD or not?

 

If you can find the differential tag or the BOM number on the housing, we can help you locate some specs on it.

Jason

 

I read on here, that all 1 ton trucks are heavy duty.

 

Duh where.

 

Let's try this again.

All Ford trucks with diesels installed are heavy duty.

Are you sure it is a Dana 70?
It could be, but more likely a 10.25" Sterling.

Here is a link to the Dana 70 info.

http://www2.dana.com/pdf/5312-9.pdf

 

Pretty sure you'll find its ford's corperate rear-the sterling rear. To the best of my knowlege dodge is the only company to use danas. Go to randys ring & pinion. Its a helpful site.

 

Yes it's a Dana 70, What I'm referring to is whether it's a 70hd axle or not. Not whether the truck is hd, Guess I shoulda been more specific.

 

Dana axles were available as special order.

If you read throgh the Dana specs in the link above it should give you the information you are looking for, that is the only Dana 70 literature on the Dana site..

 

Thanks for the link, I'll go out tomorrow and get the numbers off it. I'm debating on whether or not to swap it for the sterling in my 85.

 

I would agree that it most likely originally came with a 10.25". If it indeed has a 70, it was swapped. They quit offering rear Dana axles after '85 except for the F Super Duty trucks.

Jason

 

From my understanding Ford used Dana axles until the mid 85 model year, then they introduced the Ford 10.25.
Dana fill plugs are located in the diff. cover, while Ford 10.25 fill plugs are in the differential housing on the driver's side.
The best I.D. is that the Dana 70u has a smooth pumpkin with no ribbing.

Though I disagree with post #12, here's some good reading to help I.D. your axle.
https://www.ford-trucks.com/forums/8...-rear-end.html

I've also got a Dana 70-U in my F350 Dually. I've done a lot of reading about this axle and it doesn't impress me. It's got a 10.5" ring gear (.25" larger than the Ford 10.25), 1.5" axle shafts (Same size as Ford 10.25), and 35 Spline axle shafts (same as ford 10.25).
However, internet sources have said the carrier itself is not a true Dana 70 size, more like a Dana 60 size...thus creating a weak link. With the smaller carrier comes smaller carrier bearings.
I don't see a large selection of aftermarket Ford 10.25 axle shafts, where as Dana axles have a decent sized aftermarket...which points out the Ford 10.25 has REAL strong axle shafts in stock form. It supposedly has a unique O-Ring on the axle shaft to help retain the gear oil better than other axles.

For what it's worth, I plan on swapping my Dana 70u OUT in favor of a Ford 10.25. The Jeeps and hardcore 4x4 guys seem to like the Dana 70u because the smooth pumpkin glides over rocks or other obstructions.