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Rubicon Express Extreme Duty 5.5” TJ Lift Kit
By Chad Crowell

SKIDPLATE INSTALLATION

I painted the OME shocks black last week so they don’t stand out like a sore thumb. That yellow is pretty bright! I also re-installed my stock crossmember, removing my Metcalf flat skid, so that I wouldn’t have to deal with any surprises that came from that past installation. I brought the whole lift down to a shop we have at work that has a large air compressor and welder. I also brought along Bryan to help out. We have a total of 6 jack stands and 3 floor jacks.

The crossmember is constructed of ” thick steel plate. It is formed and cut as necessary to create a plate that is strong enough to support the drivetrain, as well as provide a solid mounting point for the arms. The frame brackets help distribute the weight and force exerted from the axles on the sides of the frame as well as the bottom. A total of 16 bolts mate the crossmember and brackets to the frame.

The crossmember is formed from 1/4 inch plate steel.
Welds are complete and brackets are strong.
The crossmember is formed from 1/4 inch plate steel.
Welds are complete and brackets are strong.

The arm mounting flanges are welded to the crossmember with good-looking beads and the whole thing is black powdercoated. The crossmember weighs a good 60 pounds, and is obviously much thicker and stronger than the stock one. The plate also is engineered to provide about 1” more clearance than the stock plate. Along with the taller springs, this provides 2-3” more clearance under the belly. All hardware provided is Grade 5 or 8.

  1. Chock the vehicle wheels and set the brake.
  2. Place a tall floor jack under the transmission with a piece of wood on it to spread the weight out.
  3. Remove the four nuts holding the transfer case to the stock crossmember.
  4. Jack up the transmission a bit.
  5. Place a floor jack under the stock crossmember.
  6. Remove the 6 bolts attaching the stock crossmember to the frame.
  7. Lower the stock crossmember out of the way and toss it like a Frisbee. You may also want to remove your stock exhaust system from the catalytic converter back to the tail pipe at this time.

    Four nuts attach the transfer case to the crossmember.
    Change your fluids if you have time...easier now then ever again!
    Four nuts attach the transfer case to the crossmember.
    Change your fluids if you have time...easier now then ever again!

  8. Raise the RE crossmember up to the frame and bolt it in using the six original holes. You may want to lower the transmission jack to make sure the tranny mount and holes in the skidplate line up correctly. Keep in mind the plate is sitting a little lower due to the nutserts that don’t yet pass into the frame.
  9. Mark the four new holes to be drilled in the bottom of the frame by placing a punch through the nutsert on the crossmember and making a mark on the frame.

    The nutserts on the plate will bolt up securely against the frame. Use a punch to mark the center of the holes to be drilled.
    The nutserts on the plate will bolt up securely against the frame. Use a punch to mark the center of the holes to be drilled.

  10. Lower the RE crossmember away.
  11. Drill a pilot hole for the four 1” holes to be drilled in the frame.
  12. Drill the four 1 1/2” holes using a hole saw and low speed drill (holes were larger than planned to clear the nutsert welds).
  13. Clean the new holes and paint to prevent rust.
  14. Raise the RE crossmember up to the frame again. The nutserts should align with the holes just drilled and the plate should fit up flush and squarely to the frame.
  15. Install the frame brackets to the frame/crossmember and bolt them up along with the crossmember by bolting in the five lower bolts on each frame rail. Make sure the brackets sit flush against the side of the frame.

    Prepare to have some tired shoulders. Fits perfectly!
    Prepare to have some tired shoulders. Fits perfectly!

  16. After checking fitment of the crossmember and the brackets, mark the holes to be drilled on the frame sides with a punch. There are three on each frame rail.
  17. Remove the crossmember and brackets.
  18. Drill a pilot hole for the six 1” holes to be drilled in the sides of the frame.
  19. Drill the six 1” holes using a hole saw and low speed drill. Only drill the outside of the frame.
  20. You will now need to pilot drill the inside of the frame rails with the center drill bit on your 1” hole saw. The 1” hole saw in the just-drilled 1” hole will help you center the back side pilot hole.
  21. Drill out the inner frame rail holes with a ” drill bit.
  22. If you won’t be welding the frame sleeves in, clean the new holes and paint to prevent rust and skip to step 28. Otherwise, clean the paint off the frame in the area where the sleeves will be welded in.

    More tired shoulders. Clean the paint from the area to be welded.
    More tired shoulders. Clean the paint from the area to be welded.

  23. Place a provided bolt through a sleeve, then place the sleeve into one of the holes just drilled. Use the bolt to hold the sleeve and keep from dropping it in the frame.
  24. Align the sleeve to the inner hole, and tack weld it in.
  25. Repeat for the other five bolts.
  26. You may want to test fit the plate and brackets for full bolt up before fully welding the sleeves in.
  27. Weld the sleeves in. Clean the areas and paint to prevent rust.
  28. Raise the plate and brackets into place, installing the 8 bolts per side as you go. Tighten up the bolts (and the nuts on the inside of the frame rails) and torque to 130 ft. lbs. Torque the bolts in the bottom of the frame to 65 ft. lbs. Be careful not to strip the factory nutserts in the frame. They tend to be soft and strip quite easily. Lower the transmission jack. The tranny mount bolts should pass into the appropriate holes in the new crossmember.

    Welding the sleeves in. Sleeves painted and ready for installation.
    Welding the sleeves in. Sleeves painted and ready for installation.

  29. Reinstall the four original tranny mount bolts.
  30. Double check all cables and wires near the area for clearance.
  31. Double check all bolts after Jeep is driven.

That wasn’t too bad…actually went quite a lot faster than I thought it would. Due to the skidplate holding the rear of the drivetrain up a bit higher, your rear driveshaft angle could be off. Also make sure your fan isn’t hitting its shroud. If you drive the vehicle as is and aren’t installing the rest of the lift immediately, you may want to remove the rear driveshaft to eliminate vibrations. Of course, in a TJ you can drive in 4Hi with the rear driveshaft removed.

Click to enlarge.  The new crossmember installed.
Click to enlarge. The new crossmember installed.

Its pretty neat looking at the new skidplate and seeing 8 bolts holding it in on each side. It looks as strong as it is. It fit up perfectly, no need to enlarge or file out any holes anywhere. And the tranny mount slid right into the holes provided for it.

Once you get the new skidplate on, you’ll notice that the muffler will be in the way of the passenger side control arm mounts. Originally, Rubicon Express furnished a kit with a bent rear upper arm to clear the stock muffler, but that is no longer an option. You will be required to buy a new muffler, and probably new exhaust piping. There is also a chance that, without a body lift, the muffler will also rub the heat shield above it.

I was told by Rubicon Express that a small aftermarket replacement muffler would work, and I ordered a 6” round muffler that didn’t come close to fitting. Rather than trying a 4” or 3” round one, I decided to take it to a local muffler shop and get their opinion. I ended up getting a completely new system on the back side of the catalytic converter and am extremely happy with it. Click here for the exhaust system details.

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