For the tj Dana 44 they are the same. The Rubicon has larger ring gear bolts and you need thick cut depending on your carrier break situation on the Rubicon or arb of your choice.
A lesson learned—keep it light and nimble!
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For the tj Dana 44 they are the same. The Rubicon has larger ring gear bolts and you need thick cut depending on your carrier break situation on the Rubicon or arb of your choice.
Boo,he set himselfup for a good line of bs about Dana 60 ring gears and you spoiled it
UKTJ
TJ Addict
OK, I am no engineer, so probably a dumb question, but here goes. How does a larger diameter help provide more strength in the context of the gears? I get a larger diameter in a tube will make something less likely to bend, but here that is surely not the concern. By zooming right in I can see that the teeth on the larger ring gear and pinion look thicker, that I get reduces the likelihood of the gear breaking. Is the size benefit just because it allows more space for thicker teeth?
With a HP dana 30 I have heard the reverse rotation adds strength to the ring and pinion, in part because the pinion is pulled into the ring gear rather than the rotation pushing it outwards under acceleration. How far does this compensate for the size difference when comparing a hp30 and a lp44?
As said above, probably dumb, but if you don't ask you don't learn.
OP
One reason for increased strength is load distribution. The 44 ring gear and pinion teeth are wider, meaning there is more surface area in contact. Specifically, the Dana 44 tooth measures approximately 1.401" at the base. The Dana 30 tooth comes in at 1.24". There may also be a slight depth difference, but that one is harder for me to measure.
A good example in how this matters wold be ice. If you walk on thin ice with just your shoes, you're concentrating all the force in a condensed area and raising the probability of the ice breaking. If however you put down a board and walked on that, you'd be spreading out the force and reducing the risk of the ice breaking.
To be clear, I'm not saying the Dana 30 R&P is weak. If it was, we'd see a lot of breakage, which we do not. I know several people that beat the crap out of their XJs and they don't break the R&P. Back to my original post on this, it's just that if you look at them side by side, the difference between the 30 and 44 is substantial. And, the picture doesn't really show just how dramatic that difference is.
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In addition to that
Moment (torque) = force x distance
If the torque is the same the bigger the distance (radius of gear) the lower the force will be.
OP
If I read this correctly, reduced deflection. Also, larger ring gears have better heat dissipation.
Reduced force on tooth and more tooth area to handle it would lead to less deflection.
Bearings further apart on the larger carrier and r&p also resist deflection. Bigger is better,until it isn't
UKTJ
TJ Addict
My question was not meant as any sort of critique, but was a genuine desire to understand where the benefit comes. I know it is often hard to distinguish genuine enquiry from trolling, but this is very much the former ( though of course I would say that even if it were the latter
).That makes perfect sense, this is a function of the greater difference between the inner and outer diameter, ie a wider ring, meaning that each tooth is longer.
UKTJ
TJ Addict
Thanks for that, though the maths of engineering is getting outside my comfort zone - bit embarrassing, but may as well be honest about it. Is what you are saying that for a set amount of torque, a bigger radius of the ring gear will mean the force appled to each tooth as it turns is proportionately less? I am guessing here that this is about leverage, but the I am far from a full understanding.
UKTJ
TJ Addict
Forgive me if This is more stupidity on display. If we are talking reduced deflection, that could be a benefit of lp44 over lp30. But as the hp30 is reverse rotation I thought the pinion was pulled into the ring gear under acceleration, doesn't this mean even further reduced deflection?
The LP44 in the rear is driving on the drive side of the ring gear and a HP30 in the front is also driving on the drive side of the ring gear going forward. Having a LP axle in the front means that you're driving on the coast side of the ring gear going forward.
This is also why you shouldn't try pulling someone who's stuck in reverse. Because then you're on the coast side of the ring gear. While strong it's the weaker side of the ring gear.
It's also why running a HP axle in the rear means that you're driving on the coast side of the ring gear.
Does this help?
UKTJ
TJ Addict
Yes, that is really helpful. I had not appreciated the point that front and rear ran the opposite way around - maybe stupid of me, but if I hadn't asked and looked dumb I still wouldn't know!
Thanks for being patient guys and helping me get a better understanding, very much appreciated!
This is what This forum is supposed to be here for. It's not a stupid question.
The added strength of running a HP axle in the front is only about 15-20٪. The main benefit is getting the front driveshaft up higher.
There is a thread on this in the reference section.
Please don't ever hesitate to ask questions.
OP
This is what makes this forum the place to go for TJ answers. Great people!
Malaysia!!
One thing that's been bugging me; the pinion gear pictured above, the longer one is the 44, right?
Happy Easter!!!
OP
Picked up a spare factory 3.73 geared Dana 44. It was a bit of a impulse buy, but I rarely see them for sale anymore and this one came of a stock jeep that wasn't abused. All the brackets are straight, the bottom of the housing isn't worn, and it only had surface rust.
My original thought is that I'll regear and add an Eaton to this one, then swap over the disc brakes. That way I can take my time and keep the Jeep mobile. We'll see if that ends up happening or not.
My original thought is that I'll regear and add an Eaton to this one, then swap over the disc brakes. That way I can take my time and keep the Jeep mobile. We'll see if that ends up happening or not.
