High Pinion Dana 44 Gear Sets

[[memphis]]

I am building a high pinion D44 (F150/Bronco) and would like to buy some spicer gears to match the rear set I am installing.

I keep finding Rubicon gears... Can these be made to work like the Jantz Jana K4? Or can I just run them? I’m assuming they are thick cut?

 

[Scott Cee aka 2drx4]

Interesting question. I am going to do some digging because this would be helpful for me if it works.

 

[SLOWPOKE693]

I think the JK ring gear bolts are a larger diameter than a regular D44 requiring the carrier holes to be enlarged. Definitely thick cut....... I'm not sure about bearings or case mods needed to fit them in an HP44 though.

 

[SLOWPOKE693]

This link will tell you everything needed to install the JK gears in an older housing:

http://jantz4x4.com/jantz.php?p=manu...a_k4&mid=jk4ig

 

[Scott Cee aka 2drx4]

This link will tell you everything needed to install the JK gears in an older housing:

http://jantz4x4.com/jantz.php?p=manu...a_k4&mid=jk4ig

Question is about the HP gears, not the LP gears. OP knows you can use the Jantz kit for the LP gears.

 

[Scott Cee aka 2drx4]

Jantz won't say if it's possible or not because he's pushing the D50 gears instead. But he eludes to that it might well be but "not worth it."

Still, the JK gears should be an actual upgrade, as the change in the gear cut was worth a fair improvement in strength. Also the thick cut gears are inherently stronger as they do have a real world decrease in ring gear deflection.

 

[Aisin]

Jantz won't say if it's possible or not because he's pushing the D50 gears instead. But he eludes to that it might well be but "not worth it."

Still, the JK gears should be an actual upgrade, as the change in the gear cut was worth a fair improvement in strength. Also the thick cut gears are inherently stronger as they do have a real world decrease in ring gear deflection.

I think the carrier would deflect before you would have to worry about the ring gear.

 

[Scott Cee aka 2drx4]

I think the carrier would deflect before you would have to worry about the ring gear.

Total deflection is a combination of the housing/caps flexing, the carrier bearings taking up internal clearances/shearing of the lubricant/compression of their components, the carrier case and flange elastically deforing, and the ring gear elastically deforming (with the carrier flange), plus the pinion deflecting the other way because all the same issues. You push on it, it bends. The total deflection is the stackup of all these parts, and controlling any one of them will decrease the total deflection. Obviously it's going to be a marginal gain, but given how thin/crappy some of the carrier flanges are it may make a real world difference.

 

[TrailTamer]

JK's D30 and D44 pinion shaft diameter is "D60 sized", while the older D30/D44/D50 are smaller. Although the pinion isn't always the weak link & I believe pre-JKD44 and D50 pinion is noticeably longer than JKD44.

I will try to remember to get my D50 & JKHPD44 ring & pinion sets (both are 4.56) and put them to each other to show how they compare.

 

['84 Bronco II]

JK's D30 and D44 pinion shaft diameter is "D60 sized", while the older D30/D44/D50 are smaller. Although the pinion isn't always the weak link & I believe pre-JKD44 and D50 pinion is noticeably longer than JKD44.

I will try to remember to get my D50 & JKHPD44 ring & pinion sets (both are 4.56) and put them to each other to show how they compare.

Please do, I'd be interested in seeing the comparison. It would be nice to take some measurements with some calipers as well.

 

[I Lean]

I'm running D50 gears in my HP D44 housing using the Jantz kit. It works well, but is a pain to install. And like it has been mentioned already, the pinion shaft is the same diameter as a D44 if you're worried about that aspect.

Fitting JK HP D44 gears in would be nifty, but you'd need to do all the R&D that Jantz already did for the D50 gears. If you have the parts and time, it might be a fun project that I would like to follow along with. :D

 

[SLOWPOKE693]

If the JK gears fit in the low pinion housing with some work, am i wrong in thinking that the front would be very similar? Like why wouldn't the Jantz LP bearing setup work in the HP or be very close to working with some mods?

I R dumb so thats probably a stupid question...

 

['84 Bronco II]

You guys do realize that the ring gear diameter of the JK HP Dana 44 gears is the same as the legacy Dana 44 ring gear diameter at 8.5", right? I am not sure that the larger pinion is enough of a strength upgrade to warrant the effort to retrofit it into legacy Dana 44 housings. The low pinion (rear) gear set that Jantz made work in low pinion legacy Dana 44s has an 8.9" ring gear, and the Dana 50 gear sets have a 9" diameter ring gear. Regardless I would like to see a comparison between the legacy HP Dana 44 gear set and the JK HP Dana 44 gear set. There were some pretty interesting pictures of the JK Dana 44 gears compared to the new JL M210 gears (HUGE pinion shaft).

 

[SLOWPOKE693]

I thought it was the cut of the gears that made the JK D44 gears stronger than the old style?

 

['84 Bronco II]

I thought it was the cut of the gears that made the JK D44 gears stronger than the old style?

That would be the new Advantek axles which have nothing in common with JK or legacy Dana axles. They have a much smaller hypoid offset in the name of efficiency, which weakens the gear set, but they claim that the M210 gearset is 8 or 9% stronger than the JK HP Dana 44 due to the "spherical torus" cut and the huge pinion shaft that probably drastically reduces pinion deflection.


EDIT: Here is the Advantek M210 gear set versus the HP JK Dana 44 gear set, both in the 5.38 flavor (Advantek on the right)

 

['84 Bronco II]

Some more information on JK HP Dana 44 vs Legacy Dana 44 from Dynatrac (https://www.dynatrac.com/blog/the-difference-between-new-generation-dana-44-axles-and-older-ones/)

NEW GENERATION DANA 44 COMPARISON CHART
Ring Gear Diam Front	1st Generation Dana 44 8.5”	Mopar JK Rubicon 44 New Generation 8.5”
Ring Gear Diam Rear	8.5”	New Generation 8.8”
Standard Ratio	3.07 through 4.56	4.10
Aftermarket Ratio Available	3.07 through 5.89	4.88, 5.13, 5.38
Pinion Shaft Diam Max	1.375	1.625”
Pinion Shaft Diam Min	1.125	1.375”
Pinion Spline	1.12” -26 spl	1.25” -24 spl
Inner Pinion Bearing OD	3.00”	3.25”
Outer Pinion Bearing OD	2.87”	2.85”
Carrier Bearing OD	3.265”	3.313”

Here’s where it gets confusing: the next generation Dana 44 uses a different sized ring gear depending on whether it is a front or rear axle. The front uses the old, 8.5-inch diameter ring gear, while the rear uses an 8.8-inch ring gear. Both the front and rear have larger diameter pinion shafts and pinion bearings with larger inside and outside diameters. The larger diameter of these components contribute to strength and stability. On the front, however, the pinion bearings are closer together compared to the first generation Dana 44. The rear has them spaced out, similar to a first gen for even greater strength.

The carrier bearings are slightly larger in diameter with the new generation Dana 44 found in Rubicon models. Another difference is found in the design of the differential. The cross-pin in the Rubicon next-gen 44 is not in the same place as the first gen, requiring different length axleshafts. The Rubicon model next-gen 44 front axleshafts also used larger steering joints and had more beef around the joints. The non-Rubicon JKs only came with a Dana 44 rear axle. The differential and carrier bearings in the non-Rubicon models are the same as the older generation 44s.

EDIT: I also found out Nitro Gear and axle is now offering complete "Jana K4" kits (they call them "big pinion" but it is in fact the 8.9" JK low pinion gear set). https://www.nitro-gear.com/category-s/673.htm

 

[Doberman Racing]

You guys do realize that the ring gear diameter of the JK HP Dana 44 gears is the same as the legacy Dana 44 ring gear diameter at 8.5", right? I am not sure that the larger pinion is enough of a strength upgrade to warrant the effort to retrofit it into legacy Dana 44 housings. The low pinion (rear) gear set that Jantz made work in low pinion legacy Dana 44s has an 8.9" ring gear, and the Dana 50 gear sets have a 9" diameter ring gear. Regardless I would like to see a comparison between the legacy HP Dana 44 gear set and the JK HP Dana 44 gear set. There were some pretty interesting pictures of the JK Dana 44 gears compared to the new JL M210 gears (HUGE pinion shaft).

I thought the front JKR d44s also used 8.8" gears too?

 

[SLOWPOKE693]

I thought the front JKR d44s also used 8.8" gears too?

Thats what I thought also. I was under the impression that the Gen 1 gears were the 03-06 Rubicon sets. And Nex Gen stuff was 07-present JK.

I have a F&R set of 5.38 JKR D44 gears sitting at home. Now I need to go look at them...


Edit: After reading that article again I think I'm right..... Maybe

 

['84 Bronco II]

I thought the front JKR d44s also used 8.8" gears too?

No, the rear ring gear is 8.875" to be exact while the front is the same as the legacy 8.5" diameter.

Thats what I thought also. I was under the impression that the Gen 1 gears were the 03-06 Rubicon sets. And Nex Gen stuff was 07-present JK.

I have a F&R set of 5.38 JKR D44 gears sitting at home. Now I need to go look at them...


Edit: After reading that article again I think I'm right..... Maybe

They stopped making JKs in 2018. JLs use Advantek axles except for the next generation Dana 30 front that is in the base models, which is basically the same thing that is in JKs. I am not sure what the difference between TJ Rubicon Dana 44 gears and legacy low pinion Dana 44s is, but they seem to be specific for some reason. I don't think TJ Rubicon gears were substantially different from all the legacy Dana 44s. I am not sure what you think you are right about.

 

[Scott Cee aka 2drx4]

They stopped making JKs in 2018. JLs use Advantek axles except for the next generation Dana 30 front that is in the base models, which is basically the same thing that is in JKs. I am not sure what the difference between TJ Rubicon Dana 44 gears and legacy low pinion Dana 44s is, but they seem to be specific for some reason. I don't think TJ Rubicon gears were substantially different from all the legacy Dana 44s. I am not sure what you think you are right about.

My understanding is that the JK gearsets use a different gear cut, while keeping the same hypoid offset. They do not look the same when placed side by side legacy D44 gears. This is supposed to be stronger as it spreads the contact area more and the pattern does not move as much under deflection, or so I have been lead to believe. The JL is again different, since they changed the hypoid offset. Now, that said, I don't know if this actually applies to the front axle.

TJ Rubicon D44 gears are thick and use a different ring gear bolt diameter, (7/16 versus 3/8, JK rear are 1/2" but I don't know about the front), but otherwise are the same to other legacy gears.

Shitty picture that doesn't show the difference in the JK gears... Best I could do.

 

['84 Bronco II]

My understanding is that the JK gearsets use a different gear cut, while keeping the same hypoid offset. They do not look the same when placed side by side legacy D44 gears.

Odd, the JK ring gear I posted next to the JL gears (Advantek) looks much more like the legacy Dana 44 ring gear in your picture, and the JK ring gear you posted looks a lot more cupped like the Advantek ring gear in the picture I posted Which of those gear sets is low pinion, they are obviously not both the high pinion gear sets which are being discussed? Maybe it is just the difference between the 5.38s and whatever ratio you took a picture of. Regardless, I wasn't aware of the HP JK gears having a "special" cut, I was under the impression that it was primarily dimensional difference in the pinion from the legacy design.

 

[Scott Cee aka 2drx4]

Odd, the JK ring gear I posted next to the JL gears (Advantek) looks much more like the legacy Dana 44 ring gear in your picture, and the JK ring gear you posted looks a lot more cupped like the Advantek ring gear in the picture I posted Which of those gear sets is low pinion, they are obviously not both the high pinion gear sets which are being discussed? Maybe it is just the difference between the 5.38s and whatever ratio you took a picture of. Regardless, I wasn't aware of the HP JK gears having a "special" cut, I was under the impression that it was primarily dimensional difference in the pinion from the legacy design.

Those are both LP gear sets. They're the same ratio, one legacy, one JK Rubicon rear.

I do not know for sure if the front gear set is like that. I also don't know if the aftermarket gears are the same, or if you need to purchase genuine Spicer gears.

 

[[memphis]]

Some more information on JK HP Dana 44 vs Legacy Dana 44 from Dynatrac (https://www.dynatrac.com/blog/the-difference-between-new-generation-dana-44-axles-and-older-ones/)



EDIT: I also found out Nitro Gear and axle is now offering complete "Jana K4" kits (they call them "big pinion" but it is in fact the 8.9" JK low pinion gear set). https://www.nitro-gear.com/category-s/673.htm

DAMN IT! Why couldn't I find that Nitro link over a month ago... I don't want to run a cheap gear set in the rear but that is super tempting! I wonder if they would sell me the bits... I have tried to contact Carl about shipping to Canada and sent him an email over a week ago.