I decided to give the case a spine.
First I made a cardboard template using the middle section of a
Samurai t-case. The plan was to make a plate that had 8
mounting tabs to hook into 8 of the mounting bolts that hold the
case together. The plate would then be bolted to a pair of
blocks, one on the short side mounting arm and one on the long side.
The spine was cut from 3/16 steel by my friend Scott at A-1
Fabrication. Scott is a wizard with anything involving
sheet metal or welding.
I left excess material along the top
and sides with the plan of whittling it down to get a close fit.
Once I had transfer punched and drilled the holes in the spine, I
attached it to the transfer case. Next I test fit in into my
rig. There were a few interferences.
After several more test fit/grind
operations, this is the shape I ended up with. I also used a
hammer to clearance the transmission tunnel corners slightly,
nothing really noticeable from the inside of the rig.
Once I knew I could slip the whole
assembly into position under the rig, it was time to fabricate the
mounting points for the spine and transfer case bucket. On the
short side I welded a block to the meaty part of the arm, transfer
punched the holes from the spine and then bolted it to the spine.
I could then weld it. It's very important to have everything
bolted together before welding to avoid any warpage due to heat.
In the first picture you'll notice
the two case bolts are recessed approximately .31" back from
the other case bolts. I simply made two small mounting tabs about
2" long, drilled a hole, then bolted them to the case.
Next I made two small 1" spacers out of 1/8" material,
slid the spacers between the spin and mounting tab, then welded the
three pieces together. The second picture shows the mounting tab
that I welded to the long side arm for the spine. I also
reinforced the section of the long side that transitions from thin
material to thick material near the transfer case mounting flange.
Once again I bolted everything back together before welding on the
bucket with the exception of the small reinforcement plate.
Unfortunately the bucket warped slightly so I ended up having to cut
the short side mount off, bolt everything together and then weld the
short side arm back on. I think if you do 1"
beads and then let the bucket cool you could avoid this.
Here's the completed case complete
You'll notice I also drilled and
tapped the PTO mounting holes on the backside of the transfer case
for M8 x 1.25 mounting bolts. I then added an arm that bolted
to the short side arm and wrapped up and around to grab two of the
PTO mounting holes. This was done when I was having
problems with my case bolts working loose. It did stop the
short side case bolts from working loose as often as they did but it
didn't seem to do much for the long side. The ultimate
solution was to replace the back half of my transfer case or
helicoil the mounting holes since the threads had been flattened out
from the bolts working loose.
After several months of hard usage I
believe the t-case spine did what I wanted it to do. I did not
have any more issues with the t-case bolts working loose and the
case itself held up to some fun full throttle assaults at the
Avalanche Ranch, a trip to johnson Valley and many trips to local
trails. I think the biggest downfall of the divorced t-case in
the Samurai is the fact that as the chassis twists, some of that
twist is also transferred thru the t-case, with the spine tying both
sides together I think the t-case did see less distortion.