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I’ve just finished installing my undercarriage armor. I used the Rock Hard 4x4 set for the engine, transmission, transfer case and fuel tank. This is not intended as a full DIY but should give someone interested in these skid plates an idea of what’s involved.

The Rock Hard skid plates are beefy (3/16” thick) and powdercoated in black. They also come with quality hardware (class 8.8 bolts, equivalent to grade 5)

Here are all the tools you need:

  • A basic socket set
  • A ¾” flat wrench or adjustable wrench
  • An Allen key set

If you want to jack up the Jeep to make things easier (you'll have to for the fuel tank plate installation), some jack and jack stands (NEVER work under a vehicle on the jack alone!)

 

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Engine oil pan and transmission skid plate

One of the things that attracted me to the Rock Hard skid plate is that it doesn’t bolt on to the bottom of the engine, rather it uses beefy brackets to bolt to the frame at the engine mounts.

In these pic it looks like the nuts could interfere with the upper control arms. I suppose I could reverse the bolts (the bolt head is thinner than the nut) but in practice I’ve wheeled with the sway bar disconnected and haven’t had a clearance issue yet.




The rear of the skid bolts to the cross member. The bolts are protected by tapered washers to minimize the risk of getting stuck on a rock:



In the past some folks complained of the skid being very close to the exhaust crossover. Rock Hard now provides a shim to improve clearance (seen here being removed when I installed their transfer case skid plate later on):



If reusing the OEM transfer case skid plate, you'll need to cut of the "lips" at the front end to make it flat and allow the washers to fit:




The plate installed. Another recent improvement is a larger oil change access door. Also note a little “wing” on the driver side, designed to protect the cat on 3.8 l engines. It doesn’t do much on the 3.6 l and in particular doesn’t protect the goofy exhaust loop.

 

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Been looking at the rock Hard transmission cross member and plate, it Looks real solid. Also the powder coating is supposed to be great on the Rock Hard equipment. I've put some pretty bad gouges in the JKU OEM one. It is still intact but I'm concerned about long term.

Yours looks great
 

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Transfer case skid plate

After wheeling for a few weeks, my suspicion was confirmed that the transfer case skid plate and the front of the fuel tank were the most vulnerable to trail rash, especially on the Unlimited. So I decided to upgrade to the whole system.
The Rock Hard transfer case skid plate is quite obviously much larger and thicker than the stock plate:




The plate is an easy bolt-on installation, sharing the cross member bolts with the engine skid plate in front and reusing the OEM bolt locations (but new bolts) in the rear. The little bolt hanging down on the right is for connecting to the fuel tank plate.



The plate is also flatter, improving ground clearance a bit in a place where this matters most:

OEM:


Rock Hard:



Fuel tank skid is next.
 

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Might need to upgrade...have the engine/oil pan skid from Rock Hard...my trans skid is hanging in, but my fuel tank skid is definitely a bit abused, right at the front as you say.
 

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Perfect timing...I am looking to do my install soon and this is very helpful.
 

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Discussion Starter #8
Fuel tank skid plate

The Rock Hard 4x4 fuel tank skid plate for the JK Unlimited is one big, heavy (69 Lbs.) chunk of 3/16” powdercoated steel.



This installation required removal of the rear wheel. My vacation home doesn’t have a garage or a paved driveway so I had to share the great outdoors with the mosquitoes…



The fuel tank shroud stays in place as it holds the tank. It’s flimsy (1/16”) and gets banged up.



Next some of the bolts have to be removed. The skid plate reuses OEM mounting points.



Holding that heavy plate in place while aligning the holes and threading the bolts can be challenging. The removed wheel made itself useful. It's also useful to leave the bolts loose to move the plate around.
While jacking up the plate to align the holes, I actually started lifting the whole Jeep. That plate will hold the weight of the Jeep without bending!



Like the engine skid plate, the Rock Hard fuel tank plate uses tapered washers at the cross member to avoid getting hung up on a rock. Nice hardware throughout.



Three holes need to be drilled through the fuel tank shroud, one in the rear wheel well, two next to the driveshaft. This is done where the shroud has a “pocket” so there’s no risk of drilling through the actual, plastic tank. A coat of RustOleum and install the bolt and locknut.




The plate installed. The loss of ground clearance is minimal; in fact the plate sits higher than the OEM transfer case skid plate did.



The view from the rear: fuel tank, transfer case and engine skid plates. One smooth expanse of sheet metal for your rock crawling pleasure. Now I have to go out and start scratching them!

 

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Looks great! Thanks for the write-up. Undercarriage armor is often overlooked by a lot of Jeepers, but it's one of the best things you can do to a Jeep if it's going to see any rocks.
 

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So I guess the fuel tank does not need to be dropped to install the skid plate.
No it doesn't. And the OEM metal shroud stays. So you end up with a total of 1/4" of tensile steel to protect those 22 gal of overpriced, highly flammable liquid.
 

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Thanks for the write up. I just ordered a set of the Rockhard aluminum skids. What did you do about your evap canister?
 

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I have the engine/trans skid and love it, my next will be the evap skid from rock hard and then to replace the factory skids with rock hard also. They make some great stuff.
 

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I installed my full set of Al skids last week with the help of this threads pictures and write up. Here are some shots of mine. NOw I just need to scratch them up!


image-651497906.jpg

Evap Canister skid

image-2909194124.jpg
 

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Thanks for the write up. I just ordered a set of the Rockhard aluminum skids. What did you do about your evap canister?
I went with the evap relocation kit (if I remember correctly, it might of also been from Rock Hard 4x4) and couldn't be happier. It is so much cleaner than adding yet another heavy skid plate. Also, I'm really happy with the oil/trans RH skid plate. It's really solid and went right on without issue.
 

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Discussion Starter #19
Thanks for the write up. I just ordered a set of the Rockhard aluminum skids. What did you do about your evap canister?
I installed the Poison Spyder evap skip. Pretty easy. See my build thread in my sig for details.
 

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I just installed the transfer case and gas tank skids on my 2014 2 door jk.
Install went quite well, but did have trouble with clearance for the bolt on the gas tank side of the little bracket that connects the gas and transfer case skid plates. Not enough space between the hole and the existing gas tank shroud for a nut, washer, and the plate. Just barely enough room for a nut+washer, so I wound up mounting the little plate on the bottom side of the skids for now.
 
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