'72 automatic tunnel insulation

[Tom L.]

Has anyone successfully replaced, without a visit to the shrink, the tunnel insulation without removing the transmission?? Mine is gone and I'd like to get it installed, just wondering if it's something that is doable since the TH400 is so large. All the clips are there so that's not an issue. Don't think it matters but it's a big block. Thanks!!

[Alan S.]

[Leif A.]

Re: '72 automatic tunnel insulation

Hi Tom,
I think not…. BUT, what I would attempt is to do it by cutting the insulator right down the middle front to back.
A person MIGHT then be able to work the 2 pieces into place from each side. And HOPEFULLY have them meet well enough at the top of the tunnel that it won't be terribly obvious what you did.
The word bubba is too good, I think the word butcher applies in this case.
Regards,
Alan

Alan,

How would he then "tape" the two pieces together? Wouldn't that just funnel all the heat straight up (heat rises) and into that one single, long seam and then right into the upper console area? Just thinking out loud...

Leif

[Steve L.]

Re: '72 automatic tunnel insulation

The insulation is held in by a number of triangular shaped pieces that are riveted to the tunnel fiberglass. These pierce thru the aluminum foil/insulation material. The triangles are then bent over to hold the insulation in place.

You would have a hard time ripping out the old insulation with everything in place. Then even a harder time trying to thread the new insulation past the engine then into the tunnel. You would probably get hung up on these triangle metal pieces and the battery cable with it's cables and bolt.

But if you don't mind shelling out a few bucks for the insulation and an afternoon. you may try Alan's method and along the way you might come up with some other ingenious method that actually works. I'm sure others would be interested in a working technique.

Instead of pushing it into the tunnel, maybe threading two small ropes on each side of the tunnel from the rear forwards, then tapping the insulation onto the ropes and pulling the insulation from the rear. You would need a helper at the engine to guide the insulation. This might be easier. Remember,, you can't push a rope,,I mean insulation. ....just a thought.

[Terry M.]

Re: '72 automatic tunnel insulation

Lowering the engine/transmission a the rear without actually removing it might work, but I have never tried. Remove the driveshaft, support transmission at the rear and remove the rear cross member and lower the rear of the transmission. Be careful of the distributor contacting the engine compartment rear bulkhead. That will be your limiting factor.That might give you enough room to sneak the insulation in using one or more of the methods already mentioned.

If you try this be sure to post a follow-up so that others will know if it works.

[Alan S.]

Re: '72 automatic tunnel insulation

Hi Leif,
Perhaps Tom could use the metal tape that residential hvac people use on duct-work joints to make the seal between the 2 pieces.
It has adhesive on it and a paper 'tape' on the adhesive face. Maybe he could work several pieces up into position and then pull the paper tape off to expose the adhesive to hold it in place.
If this doesn't work, I GUARANTEE it will be the first "make something out of nothing" plan I've ever had that didn't work.
Regards,
Alan

[Alan S.]

Re: '72 automatic tunnel insulation

Hi Leif,
Perhaps Tom could use the metal tape that residential hvac people use on duct-work joints.
It has adhesive on it and a paper 'tape' on the adhesive face. Maybe he could work several pieces up into position and then pull the paper tape off to expose the adhesive to hold it in place.
If this doesn't work, I GUARANTEE it will be the first "make something out of nothing" plan I've ever had that didn't work.
Regards,
Alan

[Michael F.]

Re: '72 automatic tunnel insulation

place jack at back of trans, disconnect the driveshaft at trans (have something to catch fluid), undo bolts on crossmember at both ends on frame, lower trans as much as you can and then try replacing. that is what I did on a 70 350/300 with auto years ago. good luck.

[Tom L.]

Re: '72 automatic tunnel insulation

To all, thanks for the help. Terry is on par with the idea I had since the transmission cross member is removable. I was hoping that someone has tried this. Doesn't look promising though.Alan, thanks a lot but I've never been a fan of tape, it's ALWAYS temporary. And BTW, I'm in the R/AC business and am very familiar with the foil tape, good stuff but by no means permanent. Just me I guess.