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Project Upsize: Axle Swap

I am starting the process of swapping the axles in my YJ.

I am swapping my open Dana 30 HP 3.07 front axle to another Dana 30 HP already geared at 4.10 plus I will be installing a Lock-Right.

I am swapping my open Dana 35 3.07 rear axle to an open Ford 8.8 geared at 4.10.

While I am addressing various aspects of my JY axles like brake rotors and pads I am also pricing my various drive shaft options. I will consolidate my final decision here, but for now I am tracking the various options here.

HP Dana 30 ($267):
Solid axle shafts from a TJ or XJ ($100)
Brake rotors ($27×2 = $54)
Check pads (good)
Rebuild calipers if necessary (good)
Extended brake lines ($85)
TRE flip
Sway bar bushings and disconnects
XJ drive shaft 1j4ff68s3xl590831 ($35)
Lock-Right locker w/ hardened pin ($296)
YAW39147-KIT Warn Vacuum disconnect block off ($40)

Ford 8.8 1fmyu24e0xub73816 w/ flange adapter ($214):
SYE ($175)
XJ drive shaft 1j4ff48s5yl174236 ($35+$93 = $128)
Replace brake pads ($27)
Check e-brake shoes (good)
Brake rotors ($31×2 = $62)
Hard brake lines ($8)
Extended brake line (Included above)
Weld Tubes ($25)
E-brake connection
Mounting kit ($118)
MORE Shock Mount Extensions ($103)

33″ Trailcutter MT ($661)

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25 thoughts on “Project Upsize: Axle Swap

  1. Work 3/7:
    Hung 8.8. Seems a bit to one side, by about 1/8″. Suspension hasn’t settled yet, so everything could settle in just right.

    The new axle did lower the rear end about 1″. I’m sure I can use a little larger shackles if need me. Or I could just mount a winch on the front to the level everything out.

    Measured the new rear drive shaft at 17.5″.

  2. Work 4/8:
    Didn’t get much accomplished today.

    The plan had been to remove the front hubs along with the axles to get ready for the locker and one-piece shaft install.

    Try as I might, the hubs would not come loose.

    I tried:
    The steering trick
    A little bit of heat (not much though)
    Soft head hammer

    I guess it’s either a slide hammer or take it to Merrill Axle.

  3. Work 3/14:
    Accomplished some tear down on the axles tonight.

    On the 8.8 I got the discs, brakelines and e-brake cabled removed.
    Tomorrow I am cutting off the ford mounts and cleaning up the areas Frontier 4×4 will be welding on.

    On HP30 I got rotors removed, the draglink off. After looking at the HP30 closely I’ve decided to swap it in directly without changing much on it. It’s actually in really good shape. Just gonna clean it up, slap a coat of paint on it and mount it up. Oh, and new brakes all the way around.

  4. Work 3/15:
    Everything removed from the HP30. Once brakes are back on and the locker installed, it’s ready to be installed.

    The 8.8 has all brackets removed. I need to clean up the old welds and clean the various areas for welding.
    I did get into the tube a bit with the grinder on one side. Jedi, the guy whose write up I am following, had the same issue and filled it in with weld. Hopefully that worked out for him and I can do the same.

  5. Work 3/18:
    Luke at Frontier 4×4 welded the tubes to the pig. Excellent beads.
    Inspected the rotors and it looks like I’ll need to replace all four.

  6. Work 3/22:
    Started disassembly of the HP30. I don’t have the option of doing the steering pop to remove the axle shafts so I am currently soaking the mating surface with PB.

    I inspected the ring gear and I cannot get the pin out without removing the carrier so that I can remove the ring gear. I am unsure if I will need a spreader to re-install it once I am done. If so, hopefully I can get one from O’Reilly’s on the loaner program.

  7. Work 3/29:
    Removed the TC drop.
    Removed the original HP30.

    The new HP30 is placed but I need to get new u-bolts. The old ones must have spread while mounted and it’s all but impossible to get them safely into the spring plates. Maybe a C clamp will work to compress them a bit and bring them to where they will get into the holes.

    There are also items to be removed from the original like the steering stabilizer.

    Ford 8.8 was cleaned up and painted. The new brakes are mounted.

  8. Work 3/31:
    Attached the front axle permanently.

    Started up the Jeep to charge the battery.

    I need to find the bushing that goes at the top of the front shock.
    Passenger side was pulled through all the way.

  9. Work 4/1:
    Tried to measure for my front drive shaft but depending on which yoke ears (always the same orientation) it varied by a half inch. I’ll wait until Saturday when I have the support of someone that’s done this before.

    I removed the stock soft brake lines and installed, but did not tighten, my new crown extended brake lines. I should have taken pictures, but I still need to figure out how to situate them.

    Hung the brake calipers on the front discs just to keep everything where it ought to be.

    Mocked up the hard brake line on the 8.8.

  10. Work 4/3:
    Disconnected rear shocks.
    Disconnected rear brakes (the hard way).
    Loosened rear shackles.
    Removed rear drive shaft (had a bad u-joint).

    Inspected the front yoke for viability when I convert to a front XJ shaft.
    Looks like I may need to get a front yoke from an XJ.

    Swept the shop so leaves don’t catch fire when welding today.

  11. Work 4/4:
    Installed SYE.
    Welded spring perches on the 8.8.

    Still to do:

    Weld shock tabs
    Fix rear brakes
    E-brake hookup
    Custom drive shaft

    Install locker
    Install solid axles
    Install block off kit
    Custom drive shaft
    New transfer case yoke
    New motor, transmission and torque arm mounts

    Torque Arm and Transmission mounts
    Rear u-bolts
    Rear shackles
    Rear flange adapter
    Front u-bolts
    Front shackles
    Front axle ears
    Front ring gear and bearings
    Both differential covers

    Rear differential
    Front differential
    Transfer case

    Finishing touches:
    Hook up vent tubes
    Connect shocks
    Bleed brakes

  12. Work 4/10:
    Took wheels to get 33 MT’s mounted.

    FINALLY got the hubs removed and old axle shafts pulled.
    Used a product called CRC Freeze Off. This stuff really works!

    I also got the carrier out to install the Lock Right.

  13. Work 4/12:

    Locker installed
    Axle seals
    Carrier re-installed
    Tube seals installed
    XJ axles installed
    Hubs re-installed
    Re-installed rotors and calipers
    Block-off kit installed

    Had some dodgy threads on one of the hubs, so I pulled one from the original axle.
    Before installing the hubs, I cleaned up the mating surfaces and coated them with hi-temp anti-seize.

    The passenger inner axle seal was a bit tricky. Since this axle assembly was a vacuum actuated it didn’t have an inner seal at the differential. During the installation of that, I had to tap the seal in a bit and test fit the axle a few times. This was to ensure the seal road on the machined surface. After that was done, I used a bit of RTV around the edge.

    When it was all said and done, I realized I installed the brake dust shields bass-ackwards, so the whole thing had to disassembled again.

    Fixed my air impact too!


  14. Work 4/13:
    Too cold to do much since the thermostat in the shop is broke but I did get the new shoes put on the YJ.

  15. Work 4/14:
    Today was a lot warmer.

    Front shocks connected
    Spring main eye and shackles torqued
    Hubs torqued
    Axle nuts torqued and keepers installed
    Steering stabilizer installed
    Steering linkage installed
    U-bolts torqued
    Diff cover installed
    Gear oil in front diff
    Brake lines attached to frame and installed on calipers
    Torqued caliper bolts
    Put the old front output yoke on until I find a XJ yoke
    PB’d front alignment hardware

  16. Work 4/15:
    Ran the HP30 vent
    Filled TC with Dextron III
    Ran the 8.8 vent
    tightened transmission and torque arm mounts
    Re-torqued rear shackles and maineyes
    Pressed the flange on the rear drive shaft
    Cut out bad brake line for replacement

  17. 4/16:
    Ran the HP30 vent
    Filled TC with Dextron III
    Ran the 8.8 vent
    tightened transmission and torque arm mounts
    Re-torqued rear shackles and maineyes
    Pressed the flange on the rear drive shaft
    Cut out bad brake line for replacement

  18. Work 4/17:
    front axle is all hooked up, filled up and torqued.
    TC is full.
    rear drive shaft is on
    brakes are all connected but having a bit of a pressure issue (see my post in tech questions) probably just air
    rear diff full, need to torque u-bolts to proper specs still

    she moved under her own power in the driveway last night.

  19. Work 4/18:
    Chris burned in the rear shock tabs and shock mount extensions
    Bleeding of the brakes began in earnest.

    By the end of the day we’d increased pressure and the Jeep was stopping better but they still aren’t stopping as well as I’d like.

    I did replace better than half the brake lines so I think I just got air trapped in a T or bend some where. More bleeding on Sunday.

  20. Work 4/19:
    Finished bleeding the brakes and got it on the road.
    Sound like one of the rear dust shields is making a bit of contact. Nothing major, will take a look later today.

    I am still going to have the brakes power-bled at a shop. I think there is still some air in the lines and will take too long to manually bleed them.

  21. More Work 4/19:
    I guess I couldn’t leave it alone.

    I found the metal to metal dragging sound. One of the rear dust shields was tweaked and making contact with a rotor.

    I also did a front alignment:
    Front of the tire: 61 1/8 – 61 3/16″
    Rear of the tire: 61 5/16″

    According to my source, just over 1/8″ but less than 3/16″ toe-in is where I should be.

  22. Work 4/20:
    Swapped out one of the calipers. I had pulled the wrong one from my pile of parts and installed it upside down.

    Finished bleeding the brakes and now they’re 5 by 5.

  23. Work 5/1 and 5/2:
    Had some trouble with over torquing the front drive shaft straps.

    I was able to drill out the broken bolt and run a tap through to cut/clean the threads. It torqued to factory spec and then some so it should hold at least until I get my new yoke ordered with u-bolts instead of the straps.

    All in all, I think the axle swap is complete minus some clean up and paint here and there.

  24. Driving:
    Been driving it since the 20th without any real issues.

    Stuff I need to check:
    TC Leak
    Finish Front Drive Shaft
    Brake Line Protection at certain points
    Inspect welds
    Seal behind shock mount extensions

    At 500 miles:
    Diff service
    Check Fluids
    Check Torque
    Trim U-bolts

  25. Finally:

    A little Ford blue peaking out the back of my YJ.

    SYE and XJ drive shaft to the 8.8.

    Not much to tell about the front since I just swapped in a HP30 with the gears I wanted. Only real upgrades were XJ solid axle shafts, Lock Right locker and another XJ drive shaft for the front.

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