Dana 70 carrier swap?

[Ranchero50]

Will a mid '80's Dana 70 carrier work in my '70 F350? I am supposed to have a posi unit from a '84 F350 with a 3.54 posi unit. The carrier number is 72697x but doesn't come up as anything except 'carrier, inactive' according to Spicer's site... It is a 46x13 gearset so it should be 3.54's if nothing else. I guess the second question is can I use that gearset with the early carrier. I see the pinion offset is .500 for the '70 and .625 for the newer stuff.

Any help appreciated.
Jamie

[Ranchero50]

no one knows?

[mlheppl]

Don't know for a fact but I'm pretty sure the answer is no. Your 70 F350 Dana 60 has 16 spline axles I believe. The Dana 70 has either 32 or 35 spline axles. Both pumpkins have the same number of bolts and the pattern looks to be the same, so it looks like the pumpkin will bolt up. If it does, you still have the axle spline count issue.

[Ranchero50]

Mike, I already have a 70 under the truck, it's a 10k camper special with the disk brakes and rear shocks, says '70' on the front of the housing. I have the complete '84 rear but the spring perches are 44 vs. 40" for the '70 and the backing plate width is wider on the 84 as well.

Jamie

[mlheppl]

Sorry my bad, I didn't realize that you have a 70 under the truck already. From what I gather, in 1984, Ford changed from the dana 70 to the dana 70HD. The 84 axle should have 35 spline axles. the info I see about the carrier is that it has a larger pinion and carrier bearings, but haven't seen any info about interchangeability on the pumpkin. Both axles used a 10 bolt 10.5" ring gear so swapping gears between the two shouldn't be a problem.

[Ranchero50]

But there's another catch, in the early 70's Dana used a .500" pinion offset, in the later stuff they used a .625 offset. According to Dustin (average F250) I should be able to turn the .125 off the carrier flange or use offset (thin) bearings and shims. Of course the axle spline count is larger on the later stuff so I'm not sure what I'll end up doing. I'd love to put the locker in if I can find the correct length axles.

I need to get the engine mounts made and get it on the road first though.

Thanks,
Jamie

[mlheppl]

You could shorten the axle tubes on the 84 rearend and then wouldn't have to worry about the difference in pinion offset, but you'd still have the same axle issue. The pictures I've seen of dana 70 axles, I did not see any taper. It looked like you might be able to cut the end of the axles down. Have you pulled the axles out to see how much spline you've got?

[Ranchero50]

I have the axle apart from the '84 but the '70 is still rolling so I'm just going to push the whole works out of the way until the truck is moving under it's own power.

Jamie

[averagef250]

You could shorten the axle tubes on the 84 rearend and then wouldn't have to worry about the difference in pinion offset, but you'd still have the same axle issue. The pictures I've seen of dana 70 axles, I did not see any taper. It looked like you might be able to cut the end of the axles down. Have you pulled the axles out to see how much spline you've got?

Pinion offset is pinion location related to carrier bearing location. Axle tubes don't effect it.

[70_F100]

You could shorten the axle tubes on the 84 rearend and then wouldn't have to worry about the difference in pinion offset, but you'd still have the same axle issue. The pictures I've seen of dana 70 axles, I did not see any taper. It looked like you might be able to cut the end of the axles down. Have you pulled the axles out to see how much spline you've got?

Pinion offset is pinion location related to carrier bearing location. Axle tubes don't effect it.

The way I understood mlheppl's post is that by shortening the tubes, Ranchero50 could put the '84 axle (complete) under the '70. That, of course, would also require shortening the axle shafts.

I don't think he was inferring that the pinion offset could be compensated for by shortening them.

Just an observation, but I've been wrong before!!!

[Ranchero50]

The '84 is wider than the '70 so I don't think that would work.

Jamie

[mlheppl]

You could shorten the axle tubes on the 84 rearend and then wouldn't have to worry about the difference in pinion offset, but you'd still have the same axle issue. The pictures I've seen of dana 70 axles, I did not see any taper. It looked like you might be able to cut the end of the axles down. Have you pulled the axles out to see how much spline you've got?

Pinion offset is pinion location related to carrier bearing location. Axle tubes don't effect it.

The way I understood mlheppl's post is that by shortening the tubes, Ranchero50 could put the '84 axle (complete) under the '70. That, of course, would also require shortening the axle shafts.

I don't think he was inferring that the pinion offset could be compensated for by shortening them.

Just an observation, but I've been wrong before!!!

Yes, that was what I was talking about, shortening the tubes on the 84 rearend, then shortening the 84 axles to match up.

[averagef250]

Gotcha. My mistake.

Not that it's never been done before, but the cost, time expense and liability of a cut down axle under a 1 ton truck doesn't seem like a great option compared to just finding the right axle or running the 84 axle at it's wider wms width. Spring pads, well, I'm sure Jamie can handle that.

[FLATBEDFORD]

You have an axle from a dually pickup, not a cab & Chassis truck. If you can find one from a C&C it will bolt right on. Even a later 10.25 should work as long as it is not from a dually pickup.