Topic: Dana 30 or 44?

[neale_rs]

The housing would be used but, is there any way (except Dynatrac) to get a new HP D44 center?  Well, I guess a JK axle...but that has the small tube diameter.

I got a quote from Currie and it was $3600 and they did not include the outer axle shafts, although an ARB brand locker was being quoted... so maybe about $3300.

The Dynatrac quote was $4600 with ARB and RCV shafts so maybe $3600 with just Dynatrac inner shafts.  About the same as Currie but with many advantages:  stronger inner Cs, brand new housing with ProRock higher ground clearance, 8.8 inch ring gear, and heavy duty diff cover.  Dynatrac really outmatched Currie on this quote.

[neale_rs]

Finally got this on order!

The final choice was the EV30YJ-ARB package deal from Superior.  This includes the ARB and Evolution series shafts with Spicer 5-760 u-joints.  The inner shafts are 30 spline, which I wanted to avoid, but a local 4x4 shop got a price that just blew away any other option.  It ended up being a bit less than the price advertised on Superior's web page, including importation and shipping to Monterrey.  Sometimes things just fall in place nicely, even the exchange rate moved in my favor recently!


Just as a side comment:  A fellow Jeeper here recently built his JK D30 with RCV shafts and the first time out on a hard trail, broke the ring and pinion.  So maybe it's better to have the 5-760 u-joints in place to act as a fuse.

[Jeffy]

Finally got this on order!

The final choice was the EV30YJ-ARB package deal from Superior.  This includes the ARB and Evolution series shafts with Spicer 5-760 u-joints.  The inner shafts are 30 spline, which I wanted to avoid, but a local 4x4 shop got a price that just blew away any other option.  It ended up being a bit less than the price advertised on Superior's web page, including importation and shipping to Monterrey.  Sometimes things just fall in place nicely, even the exchange rate moved in my favor recently!


Just as a side comment:  A fellow Jeeper here recently built his JK D30 with RCV shafts and the first time out on a hard trail, broke the ring and pinion.  So maybe it's better to have the 5-760 u-joints in place to act as a fuse.

You can put your fuse at the axle U-joints OR the driveshaft U-joints.  Or do both.  U-joints are a lot easier to fix then anything else that could go wrong.

[neale_rs]

I agree.  Based on the JK D30 experience, this would rule out Spicer u-joints in the front DS.  Would have to go with something weaker.

[Jeffy]

I agree.  Based on the JK D30 experience, this would rule out Spicer u-joints in the front DS.  Would have to go with something weaker.

I don't think you have to downgrade to anything less then a standard Spicer.

[neale_rs]

I don't think you have to downgrade to anything less then a standard Spicer.

That is very likely true for a rear axle but...

Any time a D30 ring and pinion breaks (assuming it was in good shape to begin with), it shows that the DS u-joints and the axle u-joints were stronger than the R&P in the given situation.

For a front axle with 4.56 gears,  if both front tires are bound up, the DS u-joint would need to have at most 1/(4.56/2) = 43.9 % the strength of the axle u-joints.  If only one front tire is bound up (with a locker), the DS u-joint would need to have at most 1/4.56 = 21.9 % the strength of the axle u-joints.  They would need to be pretty weak DS u-joints, so I still think a downgrade would be needed to make the DS u-joint a reliable fuse for the front axle.

A reliable DS u-joint fuse might also be obtained by relying on axle wrap. So this might be accomplished with a low pinion front axle, a single cardan DS, and a really tall lift.

[aw12345]

I did some hammer trails with 4.88 gears, 4 to1 transfercase 35" 13.5" wide krawler tires and all spicer U joints, this setup is reliable for wheelin unless of course you are determined to put a whole lot of stupid in your wheelin adventures. This whole fuse thing is way overblow. Crawl rocks. don't do a lot of wheel hopping and things will live for a long time

[FourbangerYJ]

I would agree with Art. Build everything with the best parts you can afford. Drive like you have more than 6 brain cells and things will be just fine. Everything has it's limits it's knowing them, and living within them. R&P don't break that easily if they are set up right. I have seen a number of them break, but most of it was due to the driver making poor choices. Peoples ego's break more parts than anything.

[Jeffy]

That is very likely true for a rear axle but...

Any time a D30 ring and pinion breaks (assuming it was in good shape to begin with), it shows that the DS u-joints and the axle u-joints were stronger than the R&P in the given situation.

For a front axle with 4.56 gears,  if both front tires are bound up, the DS u-joint would need to have at most 1/(4.56/2) = 43.9 % the strength of the axle u-joints.  If only one front tire is bound up (with a locker), the DS u-joint would need to have at most 1/4.56 = 21.9 % the strength of the axle u-joints.  They would need to be pretty weak DS u-joints, so I still think a downgrade would be needed to make the DS u-joint a reliable fuse for the front axle.

A reliable DS u-joint fuse might also be obtained by relying on axle wrap. So this might be accomplished with a low pinion front axle, a single cardan DS, and a really tall lift.

I'm with Art.  I wouldn't go out of my way to replace the Spicers and to say that they are too strong is a bit much.  They're a good balance and unless you're adding a lot of stupid to the equation, this shouldn't be an issue.  Things do break and not always at the fuse.

[neale_rs]

We're all with Art. Nothing beats keeping a level head and building the Jeep properly. I have no intention to downgrade my DS u-joints (I doubt something as weak as needed to serve as a reliable fuse for the front axle at the DS is even available....maybe it could be done by cutting into it on purpose.) but just saying that if you are going to design a fuse it has to be done right, with real calculations so it actually has a chance of working for you.

[aw12345]

Talking about that that is why good axle shafts for the dana 30 are of a different diam to make sure they flex equal. In other words they are made that way so the short one flexes and takes equal load as the longer one

[neale_rs]

That's one of the great features of the Superior Evolution shafts.  It's good to see that kind of design detail go into a product.