upgrading DANA 44 ring and pinion gear with a Heep JK rear r&p

[DirtDonk]

so this upgrade would probably not be worth it for mild use? I understand hard core stuff, but mild trails?

The way I see it, it's not just about trails or off-roading. You can heap just as much or more abuse on a differential on the street where you have oodles of traction as you can on the trails.
To me it's about the tire size vs gear ratio, or the gear ratio itself, or the engine torque. Or ultimately it's about the users right foot!

The dilemma with many 44 users is the lower gearing. A 4.11 is just flat out stronger than a 4.88 in a Dana axle. The pinion gear gets smaller and smaller as the numbers increase.
So going in the proper direction gear ratio wise puts your differential at a bigger and bigger disadvantage.

Basically it's all about a balance in the Force.
You have to look not only at your use, but at your tire size and gear ratio.
What's yours going to be?

Paul

 

[bknbronco]

well said paul...37's on a D44 with 5.38s and a ARB are too big for many with that lead foot.

I just spoke to Carl on the phone for a long while. He is sending out the K4 kit, a 5.38 spicer JK rear gear set, and the load bolt and intall kit. he didnt have any of the girdle covers on hand and said they take alot of time to weld up and fabricate. he said best thing is that load bolt. He also said to buy a stout cover (ruff stuff) and drill and retap for 3/8" grade 8 bolts and torque them to 50 ftlbs. Said that ties everything together and is super easy to do.

 

[sykanr0ng]

well said paul...37's on a D44 with 5.38s and a ARB are too big for many with that lead foot.

I just spoke to Carl on the phone for a long while. He is sending out the K4 kit, a 5.38 spicer JK rear gear set, and the load bolt and intall kit. he didnt have any of the girdle covers on hand and said they take alot of time to weld up and fabricate. he said best thing is that load bolt. He also said to buy a stout cover (ruff stuff) and drill and retap for 3/8" grade 8 bolts and torque them to 50 ftlbs. Said that ties everything together and is super easy to do.

Just to make sure I understand, that is replace the stock size cover bolts with 3/8 inch?

 

[bknbronco]

Just to make sure I understand, that is replace the stock size cover bolts with 3/8 inch?

correct. Get a aftermarket cover and upsize the stock cover bolts

 

[bknbronco]

https://www.youtube.com/watch?v=thxpq2akZ7g

https://www.youtube.com/watch?v=nVb5WRUfM7Y

interesting....

 

[fordguy]

and yes i did print the 14 page install manual for them load bolts last night and will read through it today.

Sounds like you need the load bolt and also need to rent a install kit as well. No problem there just have to read through everything and make sure i know what i need to do it.

can you give us a final opinion after you read and price difference. i have new carrier with 4.11s but i am going to 4.88s so the carrier i currently have will not work, right? I have a tru-trac

 

[sykanr0ng]

can you give us a final opinion after you read and price difference. i have new carrier with 4.11s but i am going to 4.88s so the carrier i currently have will not work, right? I have a tru-trac

Unfortunately you are right .
The carrier break for the D44 is 3.73 down / 3.92 up and you need the 3.73 down carrier to do this.

 

[fordguy]

i have already made the mistake of going 4.11s, but they wont be enough gear for the 4r70. trying to decide whether to just sell the whole axle instead of having it built again with 4.88s. may start a thread to see what it is worth.

 

[DirtDonk]

What's your engine going to be tuned like fordguy? If it was me (and I did actually do this) if there is any doubt whatsoever, I would wait until the engine is done, the Broncos is driving, and you're on the road with the chance to see how things work with the tire size you want.

Easier for me with my more modest tire sizes maybe, but maybe you're in that boat too? I know I've seen you talk about your build many times but I don't remember the details still. What's your setup going to be?
I know one particular Bronco running 35's with 4.11's and a stock Mustang 5.0. Even with the manual trans it handles the gearing. An auto would be even more forgiving.
It's not a road-burner by any means. But it doesn't bog down either.
I have both 4.11's and 4.56's that I can cull from luckily, and will try the 4.11's with my 4R70 with small 31's sometime. With the Explorer 5.0 even though it runs along at 65mph at only 2300 rpm in overdrive, it pulls like a tank from a stop so I know I could lower the freeway rpm and not hurt things elsewhere.
With larger tires it would be different of course, so I'm just saying there is enough leeway with these good running EFI engines that you can get away with combinations that would just not have been happy with the old stock or just carbureted engines.

Just sayin' don't stress over the gear ratio that "might" have been a mistake yet. Not until you actually KNOW it was a mistake.

Paul

 

[Broncobowsher]

i have already made the mistake of going 4.11s, but they wont be enough gear for the 4r70. trying to decide whether to just sell the whole axle instead of having it built again with 4.88s. may start a thread to see what it is worth.

Have you geared the rear yet? Before you (re)invest in front gearing you can do a 2WD test drive with just a rear gear swap. After you are really sure you like the rear gears you can do the front to match.

You will probably be ahead by just regearing and selling the barely used gears. Unless you can find a housing dirt cheap, and great deal on parts, and donate labor for free, and find someone wanting exactly the axle you are selling. If you can do all the above, then sell the whole axle and start over. Or at least start looking for what you can find a buildable axle for and just add the parts cost to fix it up. Bet that will be higher then what you can sell the whole axle for.

 

[nvrstuk]

Makes perfect sense upping to 3/8" bolts with a RS cover. They are "The Beef" and I could see where there could add some stability to a D44 housing!

Paul is right, take engine torque and multiply that with gearing like a doubler and a low/low 1st gear and you can twist anything in half even at idle!! Add stooopid tall tires, good traction , weight bias like going up a hill for the rear OR (don't do this) backing up a steep hill in reverse) and things POP and pinions blow out the front of the rear diff... I can give lots of examples when driving like a sane person and even a few when not!

 

[bknbronco]

I ordered everything from Jantz. Im not sure if he was cheeper....didnt matter....he knows the product inside and out and answers his own phone. Im out of state but everything should be at home when i get there myself.

I had 4.10's stock, last year regeared the rear to 4.88 and it didnt do shit really. So this time im going all out and going with the 5.38

I re geared my rear for a few hundred bucks, and alot or research and video watching....glad i did....ill just sell my open 4.88 to somebody for 200....maybe even less.

 

[fordguy]

What's your engine going to be tuned like fordguy? If it was me (and I did actually do this) if there is any doubt whatsoever, I would wait until the engine is done, the Broncos is driving, and you're on the road with the chance to see how things work with the tire size you want.

Easier for me with my more modest tire sizes maybe, but maybe you're in that boat too? I know I've seen you talk about your build many times but I don't remember the details still. What's your setup going to be?
I know one particular Bronco running 35's with 4.11's and a stock Mustang 5.0. Even with the manual trans it handles the gearing. An auto would be even more forgiving.
It's not a road-burner by any means. But it doesn't bog down either.
I have both 4.11's and 4.56's that I can cull from luckily, and will try the 4.11's with my 4R70 with small 31's sometime. With the Explorer 5.0 even though it runs along at 65mph at only 2300 rpm in overdrive, it pulls like a tank from a stop so I know I could lower the freeway rpm and not hurt things elsewhere.
With larger tires it would be different of course, so I'm just saying there is enough leeway with these good running EFI engines that you can get away with combinations that would just not have been happy with the old stock or just carbureted engines.

Just sayin' don't stress over the gear ratio that "might" have been a mistake yet. Not until you actually KNOW it was a mistake.

Paul

i have an efi stock explorer engine. i was just discussing the jk gear change, i wont re-gear until i drive it with the nine inch first as bowsher said. On that note, i have to buy gears in the next couple of weeks for the nine inch. I have decided to go with a tru trac differential. i have several housings for nines and an extra dana 44. maybe i just need to leave the 4.11s in the current 9 inch until i get it going, but i dont think they will be nearly enough for the 33s, but it doesnt cost anything to find out

 

[Hinmaton]

more please

First off, this is a fascinating thread.
But I am really wanting some more clarification on what exactly this means for EB front D44's.

And bkn, in case they didn't mention it in the stuff you read, the reason our 44 gears ride on the coast side is because these are "rear" axles that have been flipped around to run as a front axle. So they're being powered in what is effectively the reverse direction to go forward.
This puts the power to the coast side and vice versa.

Hence the design first used in front Dana diffs in Fords (as far as I know) making "reverse rotation" sets with the pinion up high to get the gears back to running on the drive-side for more strength.

A given ring and pinion is weaker when run in reverse than it is when run in it's original configuration (as a rear axle) so the reverse gears serve to bring most, if not all of that original build strength back.
Same problem with running a high-pinion front diff in the rear of a vehicle. It is now running on it's coast side which makes it a weaker setup to get that added ground clearance.
Not sure of all the percentages, but it's not insubstantial.

Can't wait to read how to use stronger gears in an older housing.

Paul

The statements as I understand them:
- EB D44's run on the coast side (the weak side).
- The JK ring and pinion upgrade is 44% stronger than standard D44 R&P.
- running a HP D60 in the rear is a bad idea due to running on the coast side.
- running a R&P on the coast vs conventional is multiple times weaker and should be avoided if possible.
- run reverse gears in HP front D44 if possible

This all seems fairly straight forward-ish.
So, this means that installing the JK gears is 44% stronger than the gears that are currently in there, however they are being run on the coast side, making them multiple times weaker than a conventional set up?

So, does that mean that 44% stronger the weak way is stronger than a conventionally set up HP D44? Or reverse gears in the EB D44?

Would it not make sense to put the reverse cut front D44 JK gears in the EB D44?

Can anyone clarify this?

Hinmaton

 

[sykanr0ng]

First off, this is a fascinating thread.
But I am really wanting some more clarification on what exactly this means for EB front D44's.



The statements as I understand them:
- EB D44's run on the coast side (the weak side).
- The JK ring and pinion upgrade is 44% stronger than standard D44 R&P.
- running a HP D60 in the rear is a bad idea due to running on the coast side.
- running a R&P on the coast vs conventional is multiple times weaker and should be avoided if possible.
- run reverse gears in HP front D44 if possible

This all seems fairly straight forward-ish.
So, this means that installing the JK gears is 44% stronger than the gears that are currently in there, however they are being run on the coast side, making them multiple times weaker than a conventional set up?

So, does that mean that 44% stronger the weak way is stronger than a conventionally set up HP D44? Or reverse gears in the EB D44?

Would it not make sense to put the reverse cut front D44 JK gears in the EB D44?

Can anyone clarify this?

Hinmaton

Running on the coast side is weaker but not 'many times weaker', more like 20% to 30% weaker.

You cannot put reverse cut gears in a low pinion housing like the early Bronco housing.

The JK reverse cut front ring and pinion is no larger or stronger than any other reverse cut ring and pinion and requires a high pinion housing.
Only the rear JK gears are larger and stronger, those are standard rotation.

To get stronger gears in a D44 high pinion you use the Jana 54 from Jantz, which uses the Dana 50 ring and pinion in the Dana 44 housing.

 

[Hinmaton]

I see what you are saying, and maybe i'm just not seeing it, but based on the deflection test that Jantz did in this video:
https://www.youtube.com/watch?v=aIrEuSe4B9M
I see a deflection of 2x to 3x greater on the coast side. It's my understanding that it's this deflection that causes failure in the gears.
If this is in fact true, I would say that running on the coast side is multiple times weaker = 200% to 300% weaker.
Sure- stronger is stronger, and if you follow his entire system with the load bolts and girdle maybe you could increase the percentage a lot.
But I guess I would put my money into an HP axle, take the 200-300% increase in strength right off the bat. then if I had money left over I could add load bolts and the girdle? I kind of think financially it would be a wash?

It's too bad about not being able to put reverse gears in the LP D44... anyone know why exactly? not available or not possible?


thanks,

Hinmaton

 

[sykanr0ng]

It's too bad about not being able to put reverse gears in the LP D44... anyone know why exactly? not available or not possible?


thanks,

Hinmaton

Not physically possible, the 'curve' of the gear tooth cut goes the wrong way.
That 'curve' is the whole reason they are called reverse cut.

 

[DirtDonk]

Low pinion and high pinion housings put the pinion gear in a different location, which puts it on a different portion of the ring gear. Which as was just said, puts the bevel/angle/hypoid cut in the wrong place. It's just such a precise fit, that even a few thousandths of movement in one direction or another puts the gear mesh pattern way out of whack.
Which is why they're just not compatible.

Our smaller difference in strength estimates (compared to Jantz') is based on estimates that have been around for 40 years or so, put out by Dana and other manufacturers, and spread out by the magazines back in the day, that one was "x% weaker" than the other.
Nobody here has ever tested that theory to my knowledge, so we never had any reason to doubt the conclusions of the manufacturers.

Not sure just what the original estimates were based on, or if it included deflection, or other criteria. Assume yes, but don't know. Maybe we can find some old engineering records with a google search. Lots of that kind of stuff bouncing around the internet these days.
Maybe the old engineers were referring to something else, or maybe they were not taking something into account. I tend to trust the old-school slide rule crowd pretty much though, so would love to see the methods used by both teams.
But most likely the sheer amount of deflection, as measured in inches, is not a direct correlation to torque strength or whatever the estimate results were.

After all, in the video they did not actually test anything to the breaking point. They only measured deflection. In that regard there was a lot more than 25% difference. But what about to the breaking point? What's the difference I wonder.
Be interesting to find out. As long as I'm not standing next to it when something lets go!

Paul

 

[nvrstuk]

All I know is I had the opportunity to buy a matched set of D60 axles, HiPinion for front and rear and the rear was "rear-steer". Waaay kewl factor! lol

I picked up the front and after calling at least 6 top-end builders who all unanimously confirmed that the hi-pinion rear wouldn't begin to hold up to my stroker, doublers, gearing, tire size and driving style. They all said, don't even think that the Hi-pinion 60 would hold up in the rear.

So I don't know how much this helps, but all these builders admitted they'd run a straight cut D60 in the rear in a heartbeat.

 

[Hinmaton]

Now that is a good point.
Strength and deflection may be correlated, but they are not the same.
I would like to know which is stronger. Any mechanical engineers on here?

Hinmaton