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1978/1979 HP D44 / D60 axle set: Highest numerical gear ratio?

D_JEEPER

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So my rig has a set of axles out of a 1979 F250, the HPD44 front and D60 rear. I am running a 4 banger and want to gear it as low as possible. I believe that my limitation is going to be the reverse rotation gears in the front. Right now I am looking at the 5.38s but would really like 5.89s for that extra help for my 4 banger on the street and on the trail.

Can anyone confirm that they have seen/ran 5.89s in these axles with ARB lockers?
 

D_JEEPER

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Ok well thanks for confirming my suspicions haha.
Any idea why a LP D44 will go to 5.89 whereas the HP D44 only goes to 5.38?
 

D_JEEPER

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Low pinion D44s were a common rear axle in a lot of things besides automotive. Most of those really deep ratios went into industrial things (airport tugs, zambonis, lifts, etc).
Ah ok, makes sense. :beer: Thanks!
 

Grendel

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Ok well thanks for confirming my suspicions haha.
Any idea why a LP D44 will go to 5.89 whereas the HP D44 only goes to 5.38?
Reverse rotation pinion is harder to package.
 
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WESTOF7

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Just find a lp 60 go lower and get yourself some bigger tires to compensate for the lost ground clearance :flipoff2:
 

Grendel

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5.89 Dana 44 gears are going to be pretty weak in any case.



What?
The pinion above the ring. Takes a special casting, that needs more room on top. Thus they can't space the pinion/ring out further for higher gear ratios.
 
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Dan

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The pinion above the ring. Takes a special casting, that needs more room on top. Thus they can't space the pinion/ring out further for higher gear ratios.

That's interesting, I thought they were basically the same but opposite.
 

Grendel

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That's interesting, I thought they were basically the same but opposite.
That's my understanding, anyway as to why there are less ratios.
 

'84 Bronco II

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5.89 Dana 44 gears are going to be pretty weak in any case.

That is not necessarily true and something that is blown way out of proportion on the internet and regurgitated over and over. It depends much more on the design of the gear than the ratio. In fact, lower gear ratios are stronger in some applications than higher ratios. There are plenty of people running 7.17 ratios in low pinion 60/70 combos (Dave Chapelle's Mazgrande and David Freiburger's CJ for instance), and they don't shatter as soon as you touch a rock with your tire. In fact, the pinion sees less torque in a lower ratio than a high ratio would for the same load at the tire which largely offsets any loss in tooth contact.

Granted these are 9" gears, but this illustrates my point about the ratio not necessarily being indicative of strength. One set is 5.40, the other set is 5.38.
rs=w:400,cg:true.jpg

:.jpg


The pinion above the ring. Takes a special casting, that needs more room on top. Thus they can't space the pinion/ring out further for higher gear ratios.
That's my understanding, anyway as to why there are less ratios.

What the hell are you talking about? A high pinion gear set is just a mirror image of a low pinion gear set. Same hypoid offset and same ring gear offset (why they can use the same carriers). The reason there are lower ratios available for many of low pinion Dana axle applications is due to industrial (non-automotive) applications of those axles as Vetteboy79 mentioned. Gear manufacturers apparently don't think there is enough of a market for those low ratios in high pinion applications to justify the tooling costs. Same reason why there isn't a 5.38 ratio for a Dana 70 :Homer:
 

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That is not necessarily true and something that is blown way out of proportion on the internet and regurgitated over and over. It depends much more on the design of the gear than the ratio. In fact, lower gear ratios are stronger in some applications than higher ratios. There are plenty of people running 7.17 ratios in low pinion 60/70 combos (Dave Chapelle's Mazgrande and David Freiburger's CJ for instance), and they don't shatter as soon as you touch a rock with your tire. In fact, the pinion sees less torque in a lower ratio than a high ratio would for the same load at the tire which largely offsets any loss in tooth contact.

Granted these are 9" gears, but this illustrates my point about the ratio not necessarily being indicative of strength. One set is 5.40, the other set is 5.38.
rs=w:400,cg:true.jpg

:.jpg

Wait, it's not necessarily true that a Dana 44 in 5.89 ratio is pretty weak? I You seem to have gone right into the age old debate of lower gears equal lower strength when that was not the point of the comment. Maybe you and guys like you are the reason such things are regurgitated so often.

Show us some Dana gears in the same ratio with different cuts.

The 9 inch is a whole different animal with way more aftermarket support. The fact that there are ratios available that were never offered by OE manufacturers and 10" gears and high pinion gear sets, etc puts it in a whole different category than a Dana 44.

If you look back at my post you'll see that I specifically said Dana 44 gears in a 5.89 ratio are going to be pretty weak and I still think they will be weaker than a 4.10 gearset under the same conditions. So a 4,000 lb vehicle with 300 hp and 35" tires will more than likely break a 5.89 gear set before the 4.10 in the same conditions.

I wasn't debating lower ratio being weaker in every application because I don't know that they are. I remember reading that ratios lower than 5.38 in Dana 60s are intended for industrial use and have a different cut intended for strength. Maybe that's how a 90 horse power truck and a scrambler that gets used twice a decade haven't broke any gears yet.
 

'84 Bronco II

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Wait, it's not necessarily true that a Dana 44 in 5.89 ratio is pretty weak? I You seem to have gone right into the age old debate of lower gears equal lower strength when that was not the point of the comment.

Sorry, I did not realize you were talking specifically about the 5.89 ratio, and I ASSumed you were implying that they were weak simply because they were lower than 5.38s.

Show us some Dana gears in the same ratio with different cuts.

How about the 4.09 (11T Pinion, 45T Ring) vs. 4.10 (10T pinion, 40 tooth Ring) vs. 4.11 (9T Pinion, 37T Ring) in a Dana 44? If you laid those out side by side it would look a lot like the picture of the 9" gears I posted :homer:

While having more teeth in contact at any given time is stronger than fewer (all else being equal), the size of the teeth can have a much larger impact on strength, and the teeth aren't the same size for all ratios.

If you look back at my post you'll see that I specifically said Dana 44 gears in a 5.89 ratio are going to be pretty weak and I still think they will be weaker than a 4.10 gearset under the same conditions. So a 4,000 lb vehicle with 300 hp and 35" tires will more than likely break a 5.89 gear set before the 4.10 in the same conditions.

And what data do you have to back that claim up? I assume your statement is based on the tiny teeth on a 5.89 gear set? I didn't realize they had 53 teeth on the ring gear and 9 on the pinion until I looked it up just now.

I wasn't debating lower ratio being weaker in every application because I don't know that they are. I remember reading that ratios lower than 5.38 in Dana 60s are intended for industrial use and have a different cut intended for strength. Maybe that's how a 90 horse power truck and a scrambler that gets used twice a decade haven't broke any gears yet.

There are/were plenty of people running 7.17 gears and beating on them, I just used the Daves as an example since they were two relatively high profile people running them. The 7.17 ratio uses 6 pinion teeth and 43 ring gear teeth, so they they don't have tiny teeth. For comparison, the Dana 60 has a 5.86 ratio available with 7 pinion teeth and 41 ring gear teeth, so much larger teeth relative to the 9/53 for the 5.89 ratio.
 

[memphis]

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I actually have a D60 and D44 5.89/5.86 gear sets here from a Zamboni I could measure.
 

Dan

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How about the 4.09 (11T Pinion, 45T Ring) vs. 4.10 (10T pinion, 40 tooth Ring) vs. 4.11 (9T Pinion, 37T Ring) in a Dana 44? If you laid those out side by side it would look a lot like the picture of the 9" gears I posted :homer:

Dude those are all different ratios of course they are going to have a vastly different r&p.

Haha just kidding, I didn't know they would look so different.

And what data do you have to back that claim up? I assume your statement is based on the tiny teeth on a 5.89 gear set? I didn't realize they had 53 teeth on the ring gear and 9 on the pinion until I looked it up just now.

The only data I have on the 5.89 (Dana 44) gears being weak is watching a buddy blow up 2 sets after swapping from 4.10.
 

Gravy

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A factor to take into consideration is running low pinion in a front axle is weaker than high pinion. S
 

Byro

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So no one is gonna say anything about transfer case gearing?

I have a D60 7.17 gear set and a D60 4.10 gear set at the shop I’ll take pictures of. I’m sure there is some truth to the strength of the lower (numerically) gear sets. Tooth contact being the biggest thing I can see.
 

Grendel

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What the hell are you talking about? A high pinion gear set is just a mirror image of a low pinion gear set. Same hypoid offset and same ring gear offset (why they can use the same carriers). The reason there are lower ratios available for many of low pinion Dana axle applications is due to industrial (non-automotive) applications of those axles as Vetteboy79 mentioned. Gear manufacturers apparently don't think there is enough of a market for those low ratios in high pinion applications to justify the tooling costs. Same reason why there isn't a 5.38 ratio for a Dana 70 :Homer:

Why are most HP 60 gears "thick"?
 

'84 Bronco II

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Why are most HP 60 gears "thick"?

I'm not sure I'd claim most are thick, but it is the same reason they sell thick low pinion gear sets as well. It is so you can put low gears on a high speed carrier and not have to buy a low speed carrier when you re-gear. You might notice it more with a Dana 60 because they have an inconvenient carrier break compared to most other axles (4.10 down and 4.56 up) and almost all factory 3/4 and 1 ton axles have a high speed carrier.
 

'84 Bronco II

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I actually have a D60 and D44 5.89/5.86 gear sets here from a Zamboni I could measure.

I have a D60 7.17 gear set and a D60 4.10 gear set at the shop I’ll take pictures of. I’m sure there is some truth to the strength of the lower (numerically) gear sets. Tooth contact being the biggest thing I can see.
Might as well post them up since the OP's question was answered long ago and I've already derailed the thread :laughing:

I think it would be interesting to see some side-by-side comparisons with some of the really deep ratios.
 

arse_sidewards

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Low pinion D44s were a common rear axle in a lot of things besides automotive. Most of those really deep ratios went into industrial things (airport tugs, zambonis, lifts, etc).
And it predates the HP enough that it was used in the era where high 5 and low 6 axle ratios were common because how else do you do a hill start without smoking the clutch in a 5000lbn vehicle with 2000lb shit in the bed when you only have a flathead 6 to get you moving.
 

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I’m sure there is some truth to the strength of the lower (numerically) gear sets. Tooth contact being the biggest thing I can see.
Not really.
Numerically higher ratio gear sets’ pinion are stronger. I discussed this with my engineering professor. I couldn’t prove him wrong. I did all of calculations and he’s right, pinion (drive) gear always will outlive the ring (driven) gear.

Also keep in mind you will need about 1.75 times more input torque with 4.10 to do the same amount of work as you will with 7.17.

I think part of reasons why high pinion d44 & d60 stop at 5.38 because the pinion can only spin so fast before burning up due to not completely submerged in gear oil for lubrication and cooling.
 
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