The stock transfer case crossmember does a good job of holding and protecting the transfer case and can handle a fair amount of trail abuse. Looking at it from under the truck it becomes obvious that it hangs down a little more than necessary to do the job and could provide even more projection to the aluminum housing of the transfer case. This has led a number a number of Toyota fanatics to create their own crossmembers to both gain ground clearance and provide more protection to the transfer case.

After the installation of a dual Marlin Crawler transfer case I had to modify the stock crossmember. The dual case requires the front drive shaft to be about 6.5" longer than stock and it's not possible to install the drive shaft without at least some changes to crossmember. I hammered the crossmember flat in front and notched it out a bit. It worked but still rubbed a little when the front suspension was at full extension. I was also very concerned about the trail damage to the longer transfer case as it was no longer protected.

There are several different ways to create a custom crossmember. I have seen square and round tubing, plate steel, flat bar and various combinations of these materials.

Increasing ground clearance with a custom crossmember can be done in one of two ways. The most obvious is to make the bottom of the crossmember thinner. The stock crossmember is about 2.5" where it passes under the truck and is made from molded sheet metal. It's easy  to build with materials that don't take up as much space.

The other way is to move the transfer up higher in the frame. The engine, transmission and transfer case assemble is mounted to the frame of the truck at three points; the crossmember itself and the two engine mounts. It's a simple matter to move the transfer case up a little when constructing a crossmember but drive-line angles should be considered when moving the case up. As the transfer case is lifted, U-joint or CV angles increase.

Building the Crossmember

I started the project by lifting the transfer case a little with a floor jack to take the load off the crossmember and then put a jack stand under the transmission and removed the crossmember.  I unbolted the crossmember mount from it's position on the leading transfer case and bolted it onto the rear transfer case.

I chose to build my crossmember from 1" X 3" tubing. I took my first piece and cut a  hole in it with a skill saw about 1 3/4" square. This allowed the mount to fit into the tubing. I welded the mount to the tubing with a few short welds. The welds were put on in such a way as to allow them to be removed later with a grinder if the mount ever needed to be replaced.

Next I cut out two 3/16" steel plates and drilled one hole in each plate and bolted them on the back two holes used for the stock crossmember. I created new frame mounts rearward of the stock ones using angle iron welded to the frame.

With the plates and t/case mount in place I welded more 1" x 3" steel in place. This created the basic shape. To this I added four gussets, two on each side. The gussets were created from 2" X 2" steel. Each gusset received two 45-degree cuts with a chop saw. Small plates were created from sheet metal to cover the open ends.

A large 3/16" piece of sheet metal was chosen as the skid plate. This was welded to the bottom of the crossmember. I used a floor jack to bend the the skid plate up a little in the back. After I was happy with the bend I removed the crossmember and trimmed the skid plate down to it's finished size using a skill saw with metal cutting blade. I also cut off the skid plate corners. A hole was drilled into the skid plate for drain plug access.

Primer and paint were applied and the mounting holes were drilled. I used only four of the eight stock mounting holes. Four other mounting holes were created by welding angle iron to the frame.

The final weight of the crossmember is 25 lbs (stock was 17 lbs) and my transfer cases now have good skid plate protection.  Ground clearance was increased under the crossmember by about 1", the transfer case was moved about 1/4" up from it's original position. The steel used for this project cost about $50 and it took about 20 hours to complete.