"customized" Tomken Transmission Skid - 10/31/02

When looking at skid protection for the transmission, there aren't that many options available for the Cherokee. Tomken is the only company I know that makes a transmission(only) skidplate. I say only because Rusty's and Skid Row offer a skidplate that covers both the transmission and oil pan. Actually Tomken makes one of those as well. I didn't really want one of these engine/tranny skids because of 4 reasons. 1) They engine cost 3x as much as the transmission(only) skid. 2) There have been some reports of fitting problems and even with a drain hole, I think it'll still be a hassle to do oil changes. 3) I don't think the oil pan is THAT vulnerable since with my 5"+ of lift it is tucked up high behind the front axle. 4) Weight. I already have more than enough weight on my rig!

So I decided to get the Tomken Transmission Skid. Unlike the Tomken gas tank skid, which I think is great, I am not all happy with this transmission skid due to its poor design. Read on for the details.

photo #1
Refer to photo #1 This is the Tomken skidplate. First things first - when you order it you need to specify 10" or 14". This is roughly the measurement from the front of the crossmember to the lower control arm bracket. Mine measured about 14" so thats the one I ordered. The rear of the skid fits onto the lip on the front of the crossmember and the 2 support arms are "supposed" to connect to the framerails. The problems with this skid's design are mostly in the support arms.

The biggest issue I have with the arms is it looked like I would only have 1/4" of downtravel in my driveshaft before it would hit the arm! Not good. This is mostlty because I have a low-pinion D30 (so do 2001 models) and my 5+" of lift makes clearance even less. So I don't recommend using this on a 00-01 XJ unless you are stock height or want to modify it like I did. Besides that, even though the arms are made of 1/4" steel, they are still pretty flimsy and I'm sure will bend. The skid itself is only 1/8" thick.

The arms are supposed to mount to the framerail by a rectangular piece of metal that has a threaded hole in it. This rectangular "nut" is supposed to fit into the big hole thats on the framerail. The problem is how are you going to hold the nut so it doesn't spin around while you try to thread the bolt into it? VERY poor design. (more on this later)

photo #2


photo #3


photo #4
To address the issue of the driveshaft hitting the arm, I decided I had to fab up a custom support arm or send the whole thing back to Tomken and do without. This also sucks because I don't know how to weld. But I can design it. So thats what I did and had a friend weld it up for me for $20. See photo #2. I used 1/4" thick steel that is 1.5" wide - a common size of metal that also matches the Tomken arms (I am keeping the passenger side arm). Photo #3 is just at a different angle but shows the 4 holes I drilled into it. Photo #4 shows how it fits to the skid and Tomken passenger side arm. As you can see, I designed it to go up and over the driveshaft rather than under it so the driveshaft has plent of room to move when I flex the suspension. Also, the way I'm doing it doesn't require any modification to the skid itself, it simply replaces the drivers side arm. After reading this article most of you probably won't be doing this the way I am, but if you need the measurements of my custom arm, I can send them to you upon request. If you can weld, it might be better to custom design the entire skidplate to your liking and you'd save some money along the way. I'm not done yet though, I still have to show you how I fixed the mounting problem to the framerail!

photo #5


photo #6
Here are my custom nutserts! See photo #5. The black peice is the "nut" that Tomken supplies. What I did is bought 2 metal braces from the hardware store that are a tad wider than the Tomken nuts. I made one of the holes in the brace bigger so the bolt can fit through it and thread into the Tomken nut (the brace acts like a big washer). I cut the brace shorter on one end so it would fit inside the framerail and could be positioned in the right place. After drilling and cutting the braces, I used "JB Weld" to secure the Tomken nut over the hole I drilled. If you do this, you just have to be carefull not to get JB Weld in the threads of the nut. By now some of you may be laughing at my fabrication skills, but I'll have you know, these suckers worked like a charm! The idea is when you start threading the bolt and the nut turns inside the framerail, the long brace hits the side of the framerail and stops turning, allowing you to thread the bolt in. By the way, the bolt doesn't need to have 100 LBS of torque on it either - it just needs to be tight enough to support the front of the skid and not become loose. I tightened them very snug and could probably go a lot tighter before they would break. Photo #6 is after everything was primered and painted and test fitted. Ready to go on!

photo #7


photo #8


photo #9


photo #10
The design and fabrication process was long and very involved. But the final installation was a breeze. The actual attaching it to the jeep was simple and was the easiest of any skidplate I have installed to date. I used some antiseize on the bolts that go into the nutserts so I can pull the skid off with ease in the future. Pushing up on the skid, I can tell the support arm I designed is much stronger than the Tomken one. The question is how strong is it? Hopefully the skid won't take any hits at the front because that is directly beneath the support arms. The back part of the skid is more likely to see some rocks but that doesn't really concern me because the back is where its the strongest. Overall its not the strongest skidplate ever made but it is better than nothing. Actually I do see 2 very good benefits to having it. One is since it is level with the Rusty's transfer case skid, hopefully it will help the jeep slide over rocks that would otherwise get hung up on the crossmember. See photos #7, 8, and 9 The other thing is it may protect the front driveshaft. At least it protects it a lot better than if nothing was there! See photo #10

So thats it. If the skid ever fails on me, I'll update this page and let you know. In the meantime I plan to use it, but I'm already eyeing the Rubicon Express control arm brackets. If I get them the skid's arms will be in the way and I'll have to take it off and design a whole new mounting arm : ( I really need to learn how to weld - then I could make all kinds of cool things!

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