QT Rear Diff Skid Plate
At the expense of just under half-an-inch of running ground clearance, the QT rear differential skid plate provides a 1/4-inch steel approach ramp and bash plate for the vulnerable rear differential on a Discovery. The leading edge is well thought out and bolts solidly to factory-provided holes (the same ones that hold the vibration dampener in place). I’ve whacked the skid a few times now with no trouble, but I can’t say I’m too fond of the way the trailing edge is secured. I have even heard stories of the skid being ripped off on the trail. That said, given the simplicity and low cost of this solution I am very happy with it and plan to add a matching unit up front.
Mine showed up with all the necessary hardware (the skid, a bracket, and a bolt) along with two shorter bolts for folks planning to remove the vibration dampener, but no instructions. Installation is fairly straightforward, but there are a couple tricky steps so I will detail it here.
The first thing you’ll need to do is remove the two bolts from the top of the differential shown in the first picture. If you’re Discovery is equipped with the much coveted Automatic Anti-Rust System, you’ll want to clean all the gunk from this area before moving to the next step. Next, loosely install the bracket. Thread the bolts in far enough they won’t sneak back out, but leave them out enough that you can still wiggle the bracket around.
For the next step you’re going to need a floor jack. With the jack providing support, remove the two bolts holding the dampener in place. Be very careful not to drop the dampener on yourself, it is very heavy. At this point, some folks opt to discard the dampener. If you plan to keep yours installed, the second picture shows a convenient place to set it until you’re ready to reinstall it. With the dampener safely out of the way, it’s time to install the skid plate.
The easiest way is to start with the leading ramp-edge of the skid. Make sure the trailing arm of the plate is up over the back of the differential (you won’t be able to get it in place after the fact), then start working the two front bolts into place. If you are keeping the vibration dampener, use the floor jack to hold it up and take your time. If not, use the short bolts that came with the skid plate. Remember to leave the plate loose enough you can still wiggle it. Next, move to the top-rear of the differential and line up the skid plate and bracket so you can get the small bolt in place. This is probably the most frustrating part of the entire install, just take your time. Two holes are provided on the bracket, in my case the passenger-side resulted in the best fit. Tighten the bolt just far enough to keep it from falling out, it is important that this bolt be tightened last.
Now wiggle everything around until it fits just right, while lifting the skid plate up with the floor jack until it is tight against the differential. Once it is in place, treat the two leading bolts to some blue Locktite and tighten them down. When that is done, head up top and tighten the two differential bolts holding the forward edge of the bracket in place. You’ll need to work back and forth between them so they stay even, and the bracket will bend – this is normal. Be careful not to exceed the factory specified 33 ft. lbs. of torque when tightening these bolts.
Lastly, tighten down the little bolt that joins the bracket and the skid plate. The bracket will bend to the shape of the differential, and the bolt will not extend down far enough to touch the differential cover. Lacking instructions, I opted to use blue Locktite here as well and torque the bolt down to about 75 ft. lbs.
