Is it worth buying a high pinion Dana 30?

[HornedToad]

do you actually get 3 degrees though? My understanding is that the pinion and caster are 3 degrees closer together on the HP, so for the same caster, you actually have 3 degrees lower pinion angle. If you gain 3 degrees of pinion angle by raising the driveshaft, then it ends up being a wash. I have a HP but what I haven't done is actually measure the driveshaft angle on a Jeep before and after a HP swap, all other things equal.

Low pinion Dana 30 caster/pinion separation is 12*. High pinion Dana 30 caster/pinion separation is 9*. Fancy hp44’s like rockjocks and prorocks are usually around 10*. Castor isn’t too important as long as it doesn’t get below 4*. A reduced pinion angle though is a big win because it equals a reduced driveshaft angle from the transfer case.

 

[Jerry Bransford]

I'd upgrade the rear axle and leave the front LP Dana 30 in place. I'd do a simple upgrade to 4340 27 spline inner and outer axle shafts in the Dana 30 and call it a day. That's all I did with my previous TJ's front Dana 30 and it withstood some very tough trails with 35" tires.

 

[RipSteakface]

I'd upgrade the rear axle and leave the front LP Dana 30 in place. I'd do a simple upgrade to 4340 27 spline axle shafts in the Dana 30 and call it a day. That's all I did with my previous TJ's front Dana 30 and it withstood some very tough trails with 35" tires.

I'm leaning toward this now, since I've already got the axle shafts and the balljoints... I'll just regear then.

Can the Dana 30 handle 5.13's? Or should I stick to 4.88's?

 

[Jerry Bransford]

I'm leaning toward this now, since I've already got the axle shafts and the balljoints... I'll just regear then.

Can the Dana 30 handle 5.13's? Or should I stick to 4.88's?

Yes 5.13 gearing is available for the Dana 30 and it works fine. For the front axle shafts make sure to get a 4340 shaft kit that include both the inner shafts and outer axle shaft stubs.

 

[freedom_in_4low]

Low pinion Dana 30 caster/pinion separation is 12*. High pinion Dana 30 caster/pinion separation is 9*. Fancy hp44’s like rockjocks and prorocks are usually around 10*. Castor isn’t too important as long as it doesn’t get below 4*. A reduced pinion angle though is a big win because it equals a reduced driveshaft angle from the transfer case.

those numbers are my understanding. Not arguing that it's not a big win, just unsure whether the HP30 actually offers any gain there. You have to reduce your driveshaft angle by at least 3 degrees to offset what you lost in the separation, otherwise there's no improvement to the operating angle of the front joint.

 

[HornedToad]

those numbers are my understanding. Not arguing that it's not a big win, just unsure whether the HP30 actually offers any gain there. You have to reduce your driveshaft angle by at least 3 degrees to offset what you lost in the separation, otherwise there's no improvement to the operating angle of the front joint.

The angles of separation I posted are only useful for getting an idea of what the caster angle will be and caster is only a byproduct, not something that should be designed around. When using a double carden driveshaft like the factory tj's, the pinion should be pointed directly at the transfer case output yoke. The real reason the hp Dana 30 provides less pinion angle is because the pinion starts at a higher point in space. I don't know exactly how much higher the yoke from a hp Dana 30 is off the ground from an lp Dana 30 (maybe 3"?) but whatever the difference is can be considered "less overall lift" affecting the pinion angle in regards to the whole system including suspension lift and tummy tuck lift.

 

[Wildman]

The thing that sucks about it all though is if you break your Dana 30 and want to upgrade, it's a whole new can of worms. I don't consider a Dana 44 an upgrade except for deeper gears. My next step would be tons and bigger tires but that is an entirely different animal.

Which Dana 44 are you speaking of? Yes a TJ/JK Dana 44 isn't much of an upgrade but an OLD school HP44 from a Ford is beefier than a Dana 30.

 

[freedom_in_4low]

When using a double carden driveshaft like the factory tj's, the pinion should be pointed directly at the transfer case output yoke.

while I agree with that on a rear axle that is always under load, I think there is some gray area on the free-wheeling front shaft. My last setup had 2° of operating angle on the front u-joint and had no vibrations. I didn't push it to see where the vibrations start because the caster I had was within standard specs adjusted for tire size, but if it hadn't been and I was having issues from insufficient caster, I might have done some testing to see what I could get away with. Time will tell with my LJ...gotta get my new springs installed and finish my regear before I put the front shaft in.

My standard for steering feel is a BMW. I like return-to-center.

 

[RipSteakface]

Yes 5.13 gearing is available for the Dana 30 and it works fine. For the front axle shafts make sure to get a 4340 shaft kit that include both the inner shafts and outer axle shaft stubs.

I got these 4340 axle shafts from ECGS awhile back, inners and outers.

 

[Jerry Bransford]

I got these 4340 axle shafts from ECGS awhile back, inners and outers.

Good choice, those look great!

 

[hosejockey61]

Which Dana 44 are you speaking of? Yes a TJ/JK Dana 44 isn't much of an upgrade but an OLD school HP44 from a Ford is beefier than a Dana 30.

Sure, but I still don't think it makes a difference a far as running 35's. The Dana 30 is fine for 35's. I wouldn't swap to another axle just to still run 35's. I got 8 years out of my HP30.

 

[Wildman]

Sure, but I still don't think it makes a difference a far as running 35's. The Dana 30 is fine for 35's. I wouldn't swap to another axle just to still run 35's. I got 8 years out of my HP30.

I'm not saying to swap it for 35" tires but for those who want to run 36-38" tires it is a good option that doesn't weight as much.
I'm not knocking a Dana 60 in any way and sometimes wish I'd just gotten one. But Full size Fords if you want a HP & full size Jeeps (Wagoneer/Cherokee/Pickup) had a lp44 in them and people were running 36"+ tires for a long time. No it isn't as strong as a Dana 60 but it's stronger than a TJ Dana 30/44.

 

[KERMAN]

I would not spend significant money to replace a Dana 30 with a Dana 30.

What would you spend significant money on replacing the stock Dana 30 with?

 

[freedom_in_4low]

What would you spend significant money on replacing the stock Dana 30 with?

The better question is what he considers to be significant.

I paid $150 for mine and got it all back (and then some) selling the leftovers. I was regearing anyway so I just regeared the hp and swapped them out.

 

[KERMAN]

The better question is what he considers to be significant.

I paid $150 for mine and got it all back (and then some) selling the leftovers. I was regearing anyway so I just regeared the hp and swapped them out.

So, I have yet to see a Dana 30 High Pinion at that sale price. Is that still common? And then what would you expect to pay altogehter for the gears and the whole kitten kaboodle?

 

[Longwhitejeep]

So, I have yet to see a Dana 30 High Pinion at that sale price. Is that still common? And then what would you expect to pay altogehter for the gears and the whole kitten kaboodle?

I picked my hpd30 out of a pick and pull last year for that.
Gears and axle shafts are a wash if you're running 35s since you would need them for either dana 30 axle. Shafts are same between the 2.

Only difference is the gear set and what's been mentioned previously in this thread.

 

[Good Hope]

while I agree with that on a rear axle that is always under load, I think there is some gray area on the free-wheeling front shaft. My last setup had 2° of operating angle on the front u-joint and had no vibrations. I didn't push it to see where the vibrations start because the caster I had was within standard specs adjusted for tire size, but if it hadn't been and I was having issues from insufficient caster, I might have done some testing to see what I could get away with. Time will tell with my LJ...gotta get my new springs installed and finish my regear before I put the front shaft in.

My standard for steering feel is a BMW. I like return-to-center.

I replaced a LPD30 with a HPD30 this past year and carefully measured angles throughout the process. I saw a 1 degree increase in caster angle with my 3” lift. So not nothing, but also not much. This might vary with different lifts.

The jeep drives and steers better and has better directional stability, but that could also be due to having rebuilt axle with all new ball joints, etc. Return to center is still mediocre but slightly better.

The only reason I went with HP is that I was going to rebuild the axle anyway with new gearing, axles, locker, and it only cost $120 for a good bare HPD30 housing so why not? Driveshaft length only changed by 1/4 inch so I didn’t have to replace it.

 

[NashvilleTJ]

I replaced a LPD30 with a HPD30 this past year and carefully measured angles throughout the process. I saw a 1 degree increase in caster angle with my 3” lift. So not nothing, but also not much. This might vary with different lifts.

The jeep drives and steers better and has better directional stability, but that could also be due to having rebuilt axle with all new ball joints, etc. Return to center is still mediocre but slightly better.

The only reason I went with HP is that I was going to rebuild the axle anyway with new gearing, axles, locker, and it only cost $120 for a good bare HPD30 housing so why not? Driveshaft length only changed by 1/4 inch so I didn’t have to replace it.

Also - hi-pinion ring and pinion in the front is stronger going forward compared to low pinion.

The other improvements you mentioned - besides the pinion angle - are likely because of the rebuild. I believe the axles are identical otherwise. Although it is easier to dial in more caster and still avoid vibes, so that can help with steering.

 

[afusco1222]

I replaced a LPD30 with a HPD30 this past year and carefully measured angles throughout the process. I saw a 1 degree increase in caster angle with my 3” lift. So not nothing, but also not much. This might vary with different lifts.

The jeep drives and steers better and has better directional stability, but that could also be due to having rebuilt axle with all new ball joints, etc. Return to center is still mediocre but slightly better.

The only reason I went with HP is that I was going to rebuild the axle anyway with new gearing, axles, locker, and it only cost $120 for a good bare HPD30 housing so why not? Driveshaft length only changed by 1/4 inch so I didn’t have to replace it.

I did the exact same thing. I had to rebuild the front anyways from a new rear axle with new gears so why not get a little bit stronger axle and better driveshaft clearance for a little more money. Picked my housing up for $200.

 

[MikeE024]

Just don't try to pull someone out of the mud or sand in reverse. The HP30 ring/pinion is weaker going that direction. 3* of caster gain can be huge if you plan to tummy tuck and need some caster or keeping the pinion angle happy. You'll be regearing, so the drive shafts will be spinning faster, fyi.

Just throwing this out there while the info is fresh in my head…with Yukon unlocking hubs and a stock LP44 up front w/ 5.38 gears, I’m able to focus on sufficient caster without worrying about driveline vibrations all the way up to the speedo limit that is around 95mph.

If I had to choose between a HP30 or being able to run 5.38s…and want no vibes, I’d go with the Dana 44 for the lower gearing and run a hub kit so the front DS and gears don’t turn on the road when I’m dialed in with sufficient caster angle (that in my case equates to an insufficient pinion angle).

Without the hubs I’d have vibrations from the pinion angle with properly set caster.

With the hubs up front, caster becomes priority for me rather than pinion angle, since the front end is essentially shut off when the hubs are unlocked.

Disclaimer: I’m no expert on this. I just learned much more about the front end while driving with the rear DS out…and after Blaine taught me the correct way to set front caster (I was doing it wrong).

Playing with things allowed me to (1) prioritize pinion angle, which equated to too negative of caster, and then (2) prioritize caster, which results in better steering characteristics…and the unlocked hubs prevent vibes when driving on the highway.