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TR2/3/3A Beat my transmission tunnel to death?

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bnw

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My transmission tunnel doesn't fit into my 57 worth a crap. I suppose the new floors have something to do with it and the fact that this tunnel (the whole inside of the car for that matter) must have been sitting in 4 inches of water for quite a few years. The tunnel has been welded on , whole mounting sections replaced, etc. Should I just beat it into submission? Drill new holes to match the new existing? How snug should it be around the starter side? How about the driveshaft tunnel? How should it fit up to that? I'm beginning to remember why I took three years off on this project.
 
My opinion, beat it into submission. At the tunnel, it just lays on top of the fixed part of the tunnel, hopefully with a close enough fit that a strip of felt or caulking compound will seal it. Around the starter, there is a section where it just butts up against the firewall, again hopefully close enough to seal with some caulking compound. None of mine have fit well enough to just sit in place, they have all needed to have all the bolts started first, sometimes with longer than original bolts, and with generous amounts of force applied to line the holes up well enough to start the bolts. Once you have them all started, tighten gradually to pull it into place. I have also brazed more metal around most of the original holes, as they are all split and/or rusted away.
 
I found that my tunnel went on easier before I mounted the tub to the frame. The floors can flex a lot, and so can the tunnel. I have some caulk around the starter and where it sits against the firewall as well as the drive shaft tunnel. Those last 2 bolts near the drive shaft were the most difficult to start.
 
The firewall flange needs to look like this. If it doesn't, you will have to build it up and drill it like I had to do at the bottom.
 

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I think the key is to keep the exhaust and heat out of the your area. Don't be afraid to make new lock down points and seal it.
Jerry
 
I put new floors in and found that the tunnel holes did not line up. The trick is to not tighten anything until you have all the screws started. For difficult places try using your scissor jack flat on the floor with the bottom against the outside wall and then jack the tunnel into submission at the point where the problem hole is located. I eventually got all but two holes to line up. The last two were too far out of alignment so I drilled new holes in the tunnel flange.
 
JIC some are not aware, there are replacement caged nuts available that work really slick. There's a nice article (with photos) on Mark Macy's site:
https://www.macysgarage.com/myweb6/cage_nuts.htm
I now see where he sells the nuts for $1.25 each. If you need a larger quantity, MMC sells a box of (10) for $7.21. (Scroll down to where it says "Easy-Align Weld Nuts")

They are better in every way than the originals IMO, with one exception : they need a bigger hole in the sheet metal than the originals. I found it trivial to open the hole up with a Dremel & cylindrical milling burr; but if you want, you could grind the flange off the nut housing instead. Some simple tests showed the cage to be much stronger than the TR originals, so I don't expect them to spin nearly so easily in the future (even if I do manage to live that long).
 
There are actually 2 types of tunnels. One fits the older starter and one the newer, so the bump for the starter is different on the tunnel. Berry Nelson and I debated this point, and he maintained they were all the same, but I have both. What is odd is that Berry really knows the tr3. Berry where are you? Anyways, someone also made an aftermarket fiberglass one, maybe Amco. The deal is if one needs to pull the trans or fix the shifter leakage being able to remove the tunnel easily is helpful, so my suggestion is to do a clean and nice job of fitting the tunnel, so that it comes off without too much hassle.
 
I had the same fit problems that everybody has mentioned after I put new floors in. I just chalked it up to the 50's technology when they were building these cars. That is also why I've made so many changes on my car.
 
TR3driver said:
(even if I do manage to live that long)
Click to expand...

I was thinking the same thing; I'll never be taking this tunnel off again because I have the Toyota 5-speed with hydrolic throw out bearing. I installed the tunnel while the tub was supported by 4 bar stools. All the missing or damaged captive nuts were replaced as original. I used larger washers, bent nearly in half on all the bolts. I caulked the gaps from the under side and applied undercoating to the underside and under the floors.

After my first 10 mile drive, I had to remove the tunnel. Apparently I failed to properly apply loc-tite to the shifter conversion, and it fell apart. I knew the tunnel would come off easy enough, but feared getting it back on. With an awl, I was able to line up and start all the bolts without much trouble. I think installing it before securing the tub to the frame helped.

Randall, I hope you have no plans of leaving us anytime soon. You've helped my TR3 to a new life. I'm hoping to drive through California in June and would like to visit with you, and have you see the TR3.
 
I'll confirm too...the replacement floors don't fit at all to the tunnel. Since the tunnel was original, and the floors are not, I chose to match the edge of the floor...including nut cages...to the old tunnel. Beat the lip into shape with a big hammer and dolly. When it work hardens,heat it red hot with a torch, and beat some more.
 
sp53 said:
There are actually 2 types of tunnels. One fits the older starter and one the newer, so the bump for the starter is different on the tunnel. Berry Nelson and I debated this point, and he maintained they were all the same, but I have both.
Click to expand...
Me too. Definitely different; in fact the SPC lists three different part numbers. Not sure what the earlier difference was, but it shows the tunnel changing at TS50001, which is when the bellhousing changed.
 
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