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What exactly do I need to swap a HP D30 in place of my LP D30?

C

CraigC

NAXJA Forum User
Location
Bothell, WA
Forgive me if this has been covered, but I've searched and can't find a concrete answer. There's lots of talk about the swap, but I'm interested in exactly what I need to do it. Obviously I'd need a non-disconnect HP D30, but what else do I need? New driveshaft? I understand that the LP D30 gives needed exhaust clearance on the 00-01, but I'm lifting my XJ so I don't anticipate that being an issue.
 
I've heard that you should swap the knuckles from the lp30 to the hp30 (why? I don't know). It's a good time to replace the ball joints and unit bearings too if they're shot. You may also want to hold onto the shafts from the lp30 in case you break one. If I'm mistaken about the knuckles, someone please correct me.
 
How exactly do it hit the exhaust? I looked at my '00 (no lift) and didn't see how moving the pinion higher could cause it to contact anything. Is the HP30 pinion further to the right on the back of the diff or something?
 
Crewdude007 said:
I've heard that you should swap the knuckles from the lp30 to the hp30 (why? I don't know). It's a good time to replace the ball joints and unit bearings too if they're shot. You may also want to hold onto the shafts from the lp30 in case you break one. If I'm mistaken about the knuckles, someone please correct me.
Click to expand...

Theres a difference in how the brakes mount IIRC. The knuckles are different but I I didn't swap anything around. The LP I put back into the XJ used CV's.

T3hk1w1 said:
How exactly do it hit the exhaust? I looked at my '00 (no lift) and didn't see how moving the pinion higher could cause it to contact anything. Is the HP30 pinion further to the right on the back of the diff or something?
Click to expand...

Not during "normal" road travel, but if the drivers side gets stuffed and the passenger droops it'll smoke the exhaust. It's because the pinion is higher and gets that much closer to the exhaust when you're flexing.
 
How much lift is needed to avoid that?
 
Tim_MN said:
Two steering knuckle designs were used: 1984 to 1989 and 1990 to 2001. No need or reason to swap them.

Just be aware that you might run into hub and rotor differences. Read all about it the link - http://www.jeepforum.com/forum/showthread.php?t=360959.
Click to expand...

Interesting. Thanks for pointing that out. I'd probably just swap my 2000 hubs and rotors onto a pre 1999.5 axle so I wouln't have to worry about remembering that I needed different parts there.
 
CraigC said:
Thanks guys. I was hoping it was plug and play. Now I just have to find a HP axle with the gearing I want.
Click to expand...
Why are you even doing this?
 
T3hk1w1 said:
How much lift is needed to avoid that?
Click to expand...

You should be able to avoid that with 3 inches or so I would think. If you still leave your swaybar connected i wouldn't worry about it.
 
RCP Phx said:
Why are you even doing this?
Click to expand...

Because I can likely get a 4.11 geared HP D30 for less money than it would cost me to re-gear the 3.55 LP D30 I have now. I'd rather spend less money and pick up another axle (vs. re-gearing the one I have), have it be stronger than my LP D30, and have the spare parts available that I could take off my LP D30 if I need them.
 
All you need is a HP30, some tools and time!! :thumbup:
 
I just did this recently on my 2001. I was looking to go to 4.56, and had a bit of compromise going on between castor and pinion angles with my BDS 4.5" lift.

Easy swap. I bent the LCA mount on the right side of my stock axle just about the same time I saw that someone was selling a HP 30 with fresh 4.56's in it on Craigs list. Turned out to be a member on here. I bought the axle; which I think came from a '98, cleaned up and painted the exterior of the housing, swapped in my shafts & uni bearings as assemblies along with my brake parts. Then it just bolted in.

I was able to adjust my control arms for more castor while making the pinion angle near zero. The axle also had fresh ZJ steering parts on it which was a bonus. I did have to slightly modify my engine skid plate to clear the ZJ steering

I say go for if you find one geared how you want.

Doug
 
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