dana 70

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tfinley

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I have a dana 70 out of a 1991 dodge dually. Does anyone know if work ok with a granny low transmission. I am trying to get better rpms on the highway, thanks for any help
 
That's totally dependent on what gear ratio you have now and what ratio the Dana 70 is.

Or was this a trick question?
 
The truck is a 1979 1 ton dually dana 70 with 456 gear and a 4 speed granny low. I also a 1991 dana from a dually with 307 gears. The yokes are different. I don't know if that's going to be problem. I have a nv4500 5speed that will go in the sometime. I need the truck to be better on the highway.
 
how did you figure the 3.07 gear I don't think they go any lower then 3.55.most dana 70 are 4.10 automatic trans ,3.73 with low first gear with a 16/17 inch tire
 
The rpm drop between 1st and 2nd is going to suck, you'll probably have to really wind out 1st gear but at least you'll be able to use all 4 gears. The 3.07 gears will drop you down about 1000 rpm, hope you don't have a slant 6 under the hood.
 
the 3.07 gear is a dana 61
they were used with diesel/727 combo
check the width
it may be narrower> cab/chassis vs regular dually truck

look on the housing near the carrier
it will be cast into it> 60,61, 70

most Dana 70 were 3.54

yokes will interchange, they have 29 spline on the pinion gear

the 79 yoke is 7290

the 90 is a 1350 if U bolt style
1410 if strap type

we did that swap in our car hauler
was Dana 60- 4.10 with a 440/518
to a Cummins, 5-speed, 3.07

002-3.jpg
 
So I can just pull the yokes and swap them? The 1991 rearend is about 3 inches shorter on each side but the leaf spring perches line up.
 
tfinley said:
So I can just pull the yokes and swap them? The 1991 rearend is about 3 inches shorter on each side but the leaf spring perches line up.
Click to expand...

Yes,the pinion uses shims to preload the gear
the cab/chassis> 3" shorter one

May NOT fit
If you have a dually truck bed

They are for flat bed trucks/cargo trucks
 
Sorry to be a pain. If I take the nut off and change the yoke will the pre load be a problem? I have never worked on any rearends.
 
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