How to Build an XJ Cherokee T-Case Skidplate
Low-buck do-it-yourself project at home.
While prices of used 4x4s continue to climb to astronomical levels, you can still find some bargains tucked away in dark corners of the Jeep world. While Wranglers, CJs, and fullsize Jeeps are fetching offensive money, used XJ Cherokees are still somewhat reasonable. And given that the '91-'01 XJ Cherokee came with some of the best drivetrain components Jeep ever offered in a light-duty 4x4, buying an XJ is a great way to get your foot in the off-road door without having to dump a bunch of coin on fuel injection conversions, transmission swaps, and T-case upgrades. But one area in which the Cherokee pales in comparison with its Wrangler cousin is in the undercarriage armor department. While Wranglers enjoy a large skidplate that protects the aluminum NP231 T-case, the Cherokee leaves its NP242 or NP231 T-case dangling precariously behind the skinny factory crossmember. You may be able to find a couple aftermarket skidplating options to protect the vital underbelly of your XJ Cherokee, but when I built my '99 XJ with a prerunner flavor back in 2004, I just grabbed some scrap aluminum and HREW steel tubing and whipped up my own. Here's what I came up with.
Although my Cherokee wasn't a dedicated rockcrawler, stuff happens off-road, so I wanted to make sure that vulnerable aluminum NP242 T-case had at least a little protection on the off chance I rolled over a big rock, branch, or other trail obstacle that could reach up and take a bite out of my aluminum case. I determined that a simple U-shaped hoop welded to the factory crossmember would get the job done. The first step was to buzz off the black paint so I could weld to the crossmember. The driver side had a nice large flat spot that would perfectly fit a 1.75-inch tube.
On the passenger side, I cut through the laminate sections of sheetmetal that's formed to make the factory crossmember. After cutting off part of the lip, I welded the section together and then ground it smooth. I only cut out about 2 inches of the crossmember, so when the tube was slid into place it could be perfectly welded together to regain the crossmember's full integrity. Ideally I would've cut the slot a bit narrower because I wound up having to fill a bit more of the gap with welding wire than I anticipated.
I had some 0.120-wall, 1.75-inch HREW (hot rolled electric welded) tubing lying around after a bumper build so I threw it in my tubing bender and whipped it into a U-shape. I welded on some simple, cheap 0.25-inch-thick tabs I had purchased at the local steel supply shop and then cut out a sheet of 0.25-inch 6061 aluminum. Aluminum sheet, especially T6 6061, is pretty expensive, so in lieu of using aluminum, a thinner sheet of 0.120-inch-thick steel will more than suffice. I notched a bit of the aluminum below the T-case drain plug so I wouldn't have to remove it to drain the T-case for servicing. Also, for giggles, I tossed a wire brush on my old Milwaukee drill and did some freehand brushing of the aluminum before I installed it on the vehicle just for some bling.
If you don't have a bender, you could make a square hoop with the same effect like the one I built for my 1971 CJ-6, Project Hatari! after I swapped in a longer NV3550 five-speed behind the Buick 225 V-6.
After I welded the hoop to the T-case crossmember I painted the whole thing with some black chassis paint to keep corrosion at bay.
Once the paint dried I bolted the 6061 aluminum plate to the hoop tabs using some Grade 8 hardware. Ideally I probably could have used some nice button head bolts for a sleeker look, but these are what I had on hand at the moment. The finished product ultimately was only as strong as the factory crossmember and probably would've bent a bit if I was out laying the full weight of the Jeep on it while pivoting on trail boulders every weekend. But for this build, which I used only for moderately hard off-road forays, it was plenty. The skidplate didn't hang down any farther than the factory crossmember, and it extended all the way to the end of the Tom Wood's slip yoke eliminator. It weighed very little, and aside from the relatively expensive piece of aluminum that I could have substituted a thinner piece of steel for, it only cost me a few dollars and an hour or two of garage time.