The pinion height should not generally be used as a criteria for axle selection on a TJ. Maybe the HP30 is the exception but even that is a stretch. Things like ring gear size/strength, diff clearance and ball joint vs kingpin are important for axles. High and low pinion just aren't that important. I probably have some details about the exact axles wrong but overall HP-LP is not a big deal.
Questions about axles
- Thread starter TJim
- Start date
You can if they're the right ratio. 3.55 was a lot more common in XJs though.
You can use them all the way back to 84 if you're up to deleting the CAD. Otherwise you'll want something from the 90s, and 2000 is when they went to LP like the TJ.
Mine is a CAD (deleted) from 89 XJ, with reverse cut 4.88 gears on a TJ 3.73+ carrier with knuckles and brakes and 4340 shafts from a TJ.
Yep I'm proof of that. I've managed to break 3 R&P sets in my rear HP60.
If the HP30 you find had the same gear ratio as what was in your TJ then yes you don't need to swap gears. But the point is if you have 4.88 or 5.13 gears in your LP30 and are swapping in a HP30 then you'll need new gears as LP gears will not work in a HP housing and vise a versa.
I don't fully agree with that. Just like Boom has said dragging your driveshaft thru the rocks can cause problems so running a HP axle can be helpful. You can run into fitment issues with a HP housing not clearing motor mounts or engine components. And this is where you end up having to move the axle around sometimes.
And as had already been pointed out running a rear HP axle can help with driveline angles on a SWB rig and a long travel suspension.
Yes clearance under the diff is just as important which is why companies like Dynatrac came about and why shave kits for 14 bolt and Dana 60 and Sterling axles have all happened.
I’ve heard that’s an issue with the HP60 rears.
A couple months back a buddy basically sheared his kingpin knuckle in half on his LJ on 40s… it was at a pretty small park, but in a precarious spot, I wanna say it took them about 4 hours to get it back to the trailer.
I know people on JKs and 40s that don’t break, and people on 60s and 40s that do! And they all wheel the hard lines….
A couple months back a buddy basically sheared his kingpin knuckle in half on his LJ on 40s… it was at a pretty small park, but in a precarious spot, I wanna say it took them about 4 hours to get it back to the trailer.
I know people on JKs and 40s that don’t break, and people on 60s and 40s that do! And they all wheel the hard lines….
ANYTHING can be broken. Just look at anything in the military. I've seen 2 1/2 ton and 5 ton axles broken.
Here is some more good info on the Dana 44.
https://www.therangerstation.com/tech_library/Dana44.shtml
I get it, that's exactly why I said generally. Obviously it can be a deal but overall it's on a list and for me fairly low on the list. Bent and spiraled front driveshafts seem like they happen allot less than busted diffs, busted joints, busted axle shafts and a long list of other things. Besides, the busted driveshaft is cheaper to fix than most of those other things. All this adds up to low on my personal list, that's it.
But this goes back to what you're build towards. If I'm trying to build a bulletproof rig then I'd want to move my driveshafts up out of the rocks if possible.
But we all have different priorities. I've seen enough ground down u-joints and straps and yokes that I consider it a reason to run a HP axle. And why would there be diff guards & yoke guards and such if it wasn't a problem?
More axle info just to help explain things more.