I really like the Savvy skid plate setup. Unfortunately, the good folks at Savvy don’t make a crossmember that fits the 32RH three-speed auto transmission in my 99 TJ (Not yet).
So… with some basic engineering and fabrication skills on hand, I set out to build my own custom crossmember for the Savvy skid. The design is based around AEV’s vibration isolation kit, which AEV was nice enough to sell it to me by itself along with all of their tummy tucker hardware. I mounted this on a piece of 1/4" plate.
Before I could size the support cross section, I needed to find out how much transmission dead load the crossmember would be supporting. I went about this by getting creative with a large bathroom scale.
The scale reads 225 lbs, but this includes the weight of the support blocks. However this does not include the additional weight of the removed drive shafts. As a conservative measure, I go ahead and design for 250 lbs.
On the AEV tummy tucker, the bottom of the low profile isolation pads are about an inch below the frame rails without the use of a body lift. I figured I can locate the isolation pads level with the bottom of the rails with a 1.25" body lift. Taking a straight edge along the top of the Savvy aluminum skid, I see I have about 1.25" inches for a crossmember section depth.
Time for a preliminary check of clearances… With the 1.25" inches of spacers under the isolation pads (0.25" plate + 2 x 0.5” wood boards), I jack up the Savvy skid onto the frame rails.