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Transmission Tunnel Seal

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The idea of using 100% silicone chaulk, to seal the trans tunnel, created a terrific seal between tunnel and Floor. I squeegied it smooth with a body putty applicator, it looked good and sealed perfectly. AS you know I had to remove it a few days later because I had forgotten to change out my U-joints. The silicone seal came away from the surfaces easily and came away almost as a one piece rope. This is all good. The downside is that on areas of floor/metal that I had refinished and repainted-it stuck alittle too well. I had to scrape it off and in doing that it ruined the paint. Another negative is that it is a challenge to get it chaulked-in smoothly because of the contoursions with the chaulk gun especially around the firewall. But once in it does seal. And set-up like rubber. If my car was restored and the floor flange smooth and even and painted I would diffinately take the trouble to affix a proper seal to the fibreglass tunnel. but if your car is unrestored with uneven and rusted floor flange, then the 100% silicone rubber chaulk does a very good job. I guess another condideration even with a restored car is how often do you intend to take the tunnel out. Buy the best quality you can find, the kind that says 'will not skrink'. /ubbthreads/images/graemlins/cheers.gif
 
As far as I know, on the center shift cars, the transmission cover seal set from British Car Specialists, # BCS111, works quite well. There is a front seal, two side seals, & a rear seal.

For other cars, 1/4" thick by 1" wide closed cell self stick household weather strip works ok. If you have any, Dynamat strips do the job really well. Not nearly as cumbersome as caulking.

If you ever have overdrive problems, the tunnel may come out several times.
D
 
Hi you guys,The forward and aft end of the centershift tranny cover should be treated with a standard rubber type seal. However , the floor seal would be excellent if moulded in silicone . The best of replacement seals for the floor tracks really do not do the best job. I will try next time loading the tunnel grove with silicone,placing mold release on the floor track and smoothing the silicone with an ice cube. Thanks for the feedback.---Keoke
 
Obe Wan, your points are well taken. I must say that I pride myself as being a careful and meticulous craftsman but at the same time when time and resources are at a minimum I will try just about anything. Hence the genesis of the silicone chaulk. So far I'm happy with it.
Keoke, I contimplated applying the silicone as you just described and it may be of use that way. One thing to consider in that method is that the silicone when cured does not allow for much compression. It is truely hard plyable rubber. A thick bead will not allow the tunnel to go down into its proper position. and the cured silicone may not be plyable enough to compensate for any illregularities in the mating surface. That's why I elected to apply it in fluid form after the tunnel was in place.
 
I just finished dynamating the entire inside floor and sides of my bj8. I am getting ready to line the outside of the transmittion tunnel with foil topped jute, plus foil topped jute everywhere the dnyamat was installed. Then the carpet. Now the question.

The "1/4" thick by 1" wide closed cell self stick household weather strip that Dave mentioned, I was planning on using on the front and rear of the tunnel. And also on the 1" flat rim on the bottom of the transmittion tunnel. The tunnel has a groove that keeps it in place, plus the 6 screws with large washers that screws it down. Suppose to have 6 screws, right?

Rubber seals front/back better than the foam? Why, will the foam break down?

Why silicone the bottom? Makes it hard to remove when needed. Really makes that much of a difference over using the foam stips then screwing it down for a tight fit?
Roger
 
I just tried something different. Instead of the foil backed jute between the Dynamat & the carpet, I used 1/4" thick "Volara". It is a dense closed cell Polyethelene foam. It doesn't absorb water & is not porous. Fitted & lightly glued to the back of the carpets. Less bulky & no water retention problems. I makes great gaskets/seals also. I guess there are dozens of products & ways of doing it.
D
 
Asumhly, Home made neoprene rubber seals can be laminated to take up the required space at the front and rear of the cover , are not affected by oil or grease that can deposite there and do not take a set when exposed to the heat. With regards to the silicone in the tunnel joint. Mold release is used to prevent the silicone from sticking to the floor track while the silicone will adhere to the tunnel and mold itself to fit tightly around the floor track.--Keoke.
 
Hello Roger, In my case a 1/4 inch piece of anything would not fill the gap on the front edge to firewall joint, nor on the rear tunnel to fibre glass tunnel joint. My tunnel does not have a groove for the mating of the floor flange if i understand your point there. I have a vertical flange coming up about an inch from the floor and the outer edge of the tunnel fits over that with a horizontal flange/flaring on the bottom edge of the tunnel itself. There certainly are other options to seal this removable tunnel. If you had seen what the P.O. had used you would grab at anything. this whole project just started out to be a small job to replace my emergency brake cable. It snowballed into cutting the metal tunnel away to weld the e-brake handle bracket back unto the frame, then removing all the deterorated jute backing from the old carpet, then welding in new anchor points for the seat belts, then replacing both universal joints. Removed the exhaust system to refasten the seat runners, etc. By the time I got to putting the tunnel back in place and seeing the gaps, and no idea what type of seal it was suppose to have, I was at the state of mind of saying aw jiminy it's just going to get chaulked. I might say it came out pretty well. And i know I won't have to worry about any fumes from the engine bay. If there should be some???
Dave /ubbthreads/images/graemlins/crazyeyes.gif
 
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