Art & Inspiration Tech Week – Build A Removable Trans Tunnel with Virtually No Tools

My pal Steve (31 VickyWithAHemi) asked me to toss up a tech thread or two, so here's one to get started.

I needed to build a removable trans tunnel so I could service the transmission and clutch assembly without removing the engine or body. I didn't take a lot of pictures, so there will be a few gaps in the supporting photos, but the written parts should make it clear.

1. I started out with a good size (maybe 36 x 36) piece of 18 gauge scrap that a buddy had run through his slip roll. So it was basically a big, slightly conical half cylinder. From there I worked the diameter down by bending it against my knee, leg and a 3-1/2 inch piece of pipe, to a smaller circumference, resulting in a tighter half cone shape. (sorry, no pics)
   
   
2. Then I bought some 3/4 x 1/8 (Lowe's) strapping and laid out several pieces to form the flange shape against the floor of the car. I clamped the strapping down to the floor and tacked all the pieces together. (sorry, no pics)
   
   
3. I took the flange out to finish welding the pieces together, and grind them smooth. At this point it looked like one continuous piece of strapping in the shape of my trans tunnel. (sorry, no pics)
   
   
4. Next I drilled the holes into the flange and screwed it down to a thick, flat piece of plywood. This gave me the the outer structure to fit the sheet metal cone into. I proceeded to bend the cone ever tighter, and cut the overall size down to an inch or so too large to fit into the flange I had screwed down to the plywood. (sorry, no pics)
   
   
5. From there I just bent, test-fit and trimmed until the sheet metal half cone fit into the flange. Once I was satisfied with the fit, I tacked the cone to the flange. You can see the cone, and the 3/4x1/8 perimeter I welded together. Here's a pic of this stage:
   
   
   
6. I didn't want to have to grind/dress a continuous weld down the entire seam on the top since it would show, and likely distort the 18 gauge, so I made a welding jig by cutting a hole into the plywood big enough to put the arch of the tunnel into, but small enough to still screw the flange down. This also prevented the flange from distorting while I fully welded the seam from the bottom. Here's the cone welded from the bottom in the plywood jig:
   
   
   
   
   
7. I made the spherical end from the outside of a 90° bend in a piece of left over header pipe. I cut and test fit until it was close, added a few pie cuts to get the contour right, and welded it in. (sorry, no pics before I welded it in) After grinding and filing, it looked pretty good:
   
   
   
   
   
8. I ground the welds on the bottom so the flange still sat flat on the floor of the car and then marked and drilled the holes into the floor. Once the tunnel was bolted down, I measured and marked where the shifter hole needed to be. again, I started with a very small hole and just made small adjustments to the size and position with tin snips so the shifter was perfectly centered in the hole:
   
   
   Hope that helps and good luck!

 

Very nice.

 

Sounds really easy until you go to do it. Great idea with the plywood jig for holding shape while welding. Stinks when it burns though!

 

Thanks

 

That turned out great.. thanks for posting.

 

Perfect timing I was looking at making a trans tunnel for my build Thank you for the tech!!! Jim

 

I am actually building mine right now. This will really help. Thanks

 

http://www.jalopyjournal.com/forum/threads/vote-now-tech-week-october-2015.995188/

Short time to vote

 

Designed my tunnels to come out... But they came out crappy and they worked crappier!

Great tech!

I'll use your method for the next one.

 

Suuweet!