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  • Regear an LPD30?.........

    So, I'm really just kinda spitballing here in regards to the thread question. I will regear eventually (that's my plan anyway) but I'm surveying opinions and options for now. My real dilemma is should I keep the LPD30 front end and gear it and possibly lock it or should I definitely be considering an HPD30 for gearing? The plan would be 4.56s or likely 4.88s if/when the time came. I was on the phone with Riley at 4x4Land this afternoon and he mentioned the HP is 27% stronger. Am I a fool for thinking the LP would suffice? A good handful of folks in here have been on the trails with me and know my flavor of wheelin......

    So.........what say you KCJC?

    Brian (MountainGoat) - already know what you'll say. ;)
    Last edited by JeepN4kc; 08-29-2014, 08:01 PM.
    -Mike B-
    '01 XJ Sport
    '11KK Limited

  • #2
    get at least a HP dana 30 ! ... and go with 4.88 s ! ... you have an overdrive tranny, so go for what ya can ! ;)
    I may be Rad and I may be Bad :pbj: but I am never SAD ! :kilt:
    Yea I'm *Q*C* and ?
    it is a great feeling to have served your country and walk PROUD
    Yes veterans stand tall and their shadow protects all !

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    • #3
      I always believed that front is a weak link and gearing and a locker could improve traction, but can also cause more opportunity to break too.

      Why not save your money and find a good matching set of axles in a wrecked or beater and slap gears and lockers in them.

      Comment


      • #4
        What are you plans with the rig as far a tire size, aftermarket axles and locker?
        sigpic
        MIDWESTWHEELER

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        • #5
          Originally posted by spunebil View Post
          get at least a HP dana 30 ! ... and go with 4.88 s ! ... you have an overdrive tranny, so go for what ya can ! ;)
          4.88s will likely be the route.

          Originally posted by alanc View Post
          I always believed that front is a weak link and gearing and a locker could improve traction, but can also cause more opportunity to break too.




          Why not save your money and find a good matching set of axles in a wrecked or beater and slap gears and lockers in them.
          Well the 29 spline 8.25 in the rear is a good axle so all I'm even considering is the front end.

          Originally posted by Troyb_78 View Post
          What are you plans with the rig as far a tire size, aftermarket axles and locker?
          Tires I'd most likely stay at 33s.......maybe 35s down the road but 33s are a good fit, honestly. Aftermarket axles.......maybe go with some chromo shafts down the road. Locker, already have an Aussie in the rear and I really am pleased with it. Front I would love a selectable but another lunchbox in the front is something I'm not against.
          -Mike B-
          '01 XJ Sport
          '11KK Limited

          Comment


          • #6
            Need to be honest with yourself, living in reality. If one has a heavy right foot, its just a matter of time before the pinion or ring gear are shock loaded and broken regardless of 33 or 35" tire or what you do to spruce up a d30. Might as well start looking at D44-60s, hybrid 9s, something that is larger.

            IMO if you your dedicated to staying with 33" tires, and open in the front, a LP D30 would work fine with a common sense wheeling style. Its going to be cheaper all the way around.

            Gear ratios? A couple of thoughts:

            1. I would go with 4.56 gears verses the 4.88s. I have 4.10s and the pinion is the size of a large walnut or a golf ball, imagine what size a 4.88s is? A 3.54 pinion is baseball-softball sized in comparison to a 4.10 pinion.

            2. Gear the axles to reach the sweet spot on the torque curve at highway speeds. As an example, the sweet spot in the torque curve arrives at 2400-2500rpm, then gear to reach that rpm at 65-70mph. If this is a DD or wheeled too and from the trail on a regular basis, then I would definitely make this a consideration.

            Something else I would consider, especially if one is skimping on the front locker, an upgraded differential cover. It will provide some protection for the gears and help some with axle housing flex.

            I don't know how strong XJ stub shafts are? That would help me determine the need for chromo shafts.

            If the OEM shafts allow for a 297x or 760x U joint, then the U joint should be strong enough for moderate wheeling with a 33" tire unlocked. (common sense wheeling)

            A 260x joint, in an OEM axle, is going to be marginal at best with a 33" tire. Its been a couple of years ago now, but I broke 6 260x U joints, 3 stub shafts (at the ears) in a 6 week period of wheeling! I was locked on 35" tires and not real smooth with my driving style. 260x U joints and 33"+ tires at the minimum will require increased maintenance. If that maintenance is ignored i.e. replaced as soon as there is some play in the joint, it can fail and take the stub shaft with it or worse knocking your outer knuckle off ball joints! Of course it will happen at the most inopportune time!

            Last thought: Have you considered building an HP D30 as time and money allows, and NOT molesting your current axle housing? My thinking is that you could do a whole bunch of stuff over time i.e. sleeve axle tubes, upgrade your ball joints, 30 spline locker and axle shafts, new seals, etc etc etc. Then drop it in when you're ready to regear the rear?

            Things I think about,
            Wally
            Last edited by WallyP226; 08-31-2014, 06:51 PM.

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            • #7
              Wally -

              I tend to err on the side of caution in regards to the throttle, and I'd like to get even lighter with a good slow crawl. I hadn't considered the smaller mass in the deeper gears so you got me thinking on that one. As far as what this rig does on the road - not a priority. I trailer it to the trails. It is street legal for when I'm tooling around town or need to get from one place to the next on pavement but as long as it will roll down the road and is licensed and tagged it's good enough for me. I already run Solid diff covers f/r. Replaced the ujoints about 6 months ago (old ones were the original stockers) with Spicer 5-760x and also replaced the stocker hub bearings with new oe units.

              As for your last thought - this is actually something I have thought of over the last couple days and your reiteration makes me think it would be the smart thing to do. I do fall back on your assessment that staying on 33s and common sense would allow the LP to serve me well.

              Thanks a bunch for your thoughts!

              Decisions, decisions..........
              -Mike B-
              '01 XJ Sport
              '11KK Limited

              Comment


              • #8
                Something else that I thought of.

                You might consider doing a cost analysis between building a HPD30 and D44? When I built my HP D30, I was within $500 of LP D44.

                FWIW I followed my own advice and I have been satisfied with building the HP D30. 3500lb Jeep on 35" tires, Detroit locker in the front. I went with 27 spline chromo axles and 760x U joint.

                I have not had any real issues since building it but in fairness to all viable options its something to think about.

                Wally

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                • #9
                  Budget! The basic difference between the HP vs LP is obvious the r&p. Everything else will bolt-on across either way. I started off with the stock TJ front which is crush sleeve bearing and LP. Went with used Easy Locker (Detroits lunchbox) with new pins and coils and 4.88s. In time, I added new ball joints, brake pads, and went through several shafts and joints. You know how I wheel. 6 yrs later, chipped several ring teeth in Clayton. Swapped in 95 XJ front D30HP and swapped everything over except r&p. Wheeled that way for 3 yrs, till last Frostbite when my carrier shattered. In time with that axle, I swapped in set of RCVs. Rebuilt that housing adding Grizzly locker (Yukon case locker) and new gears. Broke RCV shaft at locker and destroyed the bearing, cap, race, housing race,....
                  Went with another XJ D30HP front. Swapped everything over and still wheeling it!

                  For how you wheel and plan to upgrade, the D30 LP is fine. Once you have issues, with anything r&p related, swap in a HP. Everything will bolt across it.
                  Mike
                  Jagular7

                  Lnxa, KS

                  Comment


                  • #10
                    Originally posted by WallyP226 View Post
                    Something else that I thought of.

                    You might consider doing a cost analysis between building a HPD30 and D44? When I built my HP D30, I was within $500 of LP D44.

                    FWIW I followed my own advice and I have been satisfied with building the HP D30. 3500lb Jeep on 35" tires, Detroit locker in the front. I went with 27 spline chromo axles and 760x U joint.

                    I have not had any real issues since building it but in fairness to all viable options its something to think about.

                    Wally
                    That is something to consider I suppose but I like the idea of being able to swap in the front axle myself in the garage. A D44 swap is more involved and not something I'm prepared to or equipped to handle as far as diy.

                    Originally posted by jagular7 View Post
                    Budget! The basic difference between the HP vs LP is obvious the r&p. Everything else will bolt-on across either way. I started off with the stock TJ front which is crush sleeve bearing and LP. Went with used Easy Locker (Detroits lunchbox) with new pins and coils and 4.88s. In time, I added new ball joints, brake pads, and went through several shafts and joints. You know how I wheel. 6 yrs later, chipped several ring teeth in Clayton. Swapped in 95 XJ front D30HP and swapped everything over except r&p. Wheeled that way for 3 yrs, till last Frostbite when my carrier shattered. In time with that axle, I swapped in set of RCVs. Rebuilt that housing adding Grizzly locker (Yukon case locker) and new gears. Broke RCV shaft at locker and destroyed the bearing, cap, race, housing race,....
                    Went with another XJ D30HP front. Swapped everything over and still wheeling it!

                    For how you wheel and plan to upgrade, the D30 LP is fine. Once you have issues, with anything r&p related, swap in a HP. Everything will bolt across it.
                    Thanks for the input - I really like the idea of being able to bolt everything over. I never knew you ran on an XJ front end.....and I thought those RCVs were touted as being bomb-proof...
                    -Mike B-
                    '01 XJ Sport
                    '11KK Limited

                    Comment


                    • #11
                      I've built a HPD30 before. I don't think it was worth the effort. Granted I am harder on stuff and I typically wheel 4+ trails, but I managed to destroy the spiders and carrier with NO LOCKER running 35s. I've seen several HP30s destroy R&P gears and by the time you truss the housing to mitigate flex you will have nearly as much in the D30 as you will a D44, and the R&P and shafts will still be weaker.

                      Here were my original plans for my TJ on 35-36" tires before I lost my mind and went to D70s and 40s.

                      High Pinion D44 from 78-79 F150 ($200-$300 on CL)
                      Assume it will need full rebuild with ball-joints, brakes, etc. ($250 ish)
                      Regearing and bearings wouldn't cost much more than a D30 ($600 or so inc. labor)
                      Welded front diff (new diffs for your carrier break are $60-$80 on ebay)
                      Have someone like 4x4 Land cut it down to Jeep (waggy) or Scout width, reweld the inner Cs and add a factory style bracket kit ($400-$500 is my guess)
                      OEM Waggy or Scout shafts ($100-$200)
                      6x5.5" pattern spacers out back to match front pattern ($75)
                      Wheels to match pattern ($200 or less if you use CL)

                      That front axle should be all that you need for an XJ on up to 36" tires if you're not hard on the throttle.

                      Comment


                      • #12
                        Originally posted by JeepN4kc View Post
                        Thanks for the input - I really like the idea of being able to bolt everything over. I never knew you ran on an XJ front end.....and I thought those RCVs were touted as being bomb-proof...
                        They probably are. Bet I set a nice crack that was missed during inspection before being put back in. I broke it at the splines as the carrier. Then driving some 100 yds on it, shredded that area all the way out to the diff housing race!
                        I also had the tubes sleeved anticipating flex and didn't want to mess with a locker splitting case issue. I had a ARB in my XJ for 9 yrs. I went through 3 due to the housing flex and shearing the case bolt heads off. Lunchbox didn't have an issue. My current setup is a full case Grizzly and there hasn't been a sign of an issue.

                        I like my D30HP on my TJ with the 35s.
                        Mike
                        Jagular7

                        Lnxa, KS

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