New commercial mount for 2004R transmission

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Dart Vadr

Dart Vadr

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My 1967 Dart GT is currently being refurb'd at US Car Tool. While there, I had them build a mount for the Extreme Automatics GM 2004R transmission that's going behind my stroked 340. They've decided to sell the mount as a commercial product. Obviously, the kit will require some cutting and welding, but it might be a good option for folks without extensive fabrication skills. I can't give you an exact cost as they're still working out the pricing details, but what they charged me is quite reasonable. Just wanted to let folks know that there's a commercial option out there for A-Bodies. I've included some pictures for your viewing pleasure.
 

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Nice looking, BUT, this crossmember does more then hold up the transmission. It supports the torsion bars, and it is a crash part. Those angles are scary. IMO.
 
Dart Vadr said:
My 1967 Dart GT is currently being refurb'd at US Car Tool. While there, I had them build a mount for the Extreme Automatics GM 2004R transmission that's going behind my stroked 340. They've decided to sell the mount as a commercial product. Obviously, the kit will require some cutting and welding, but it might be a good option for folks without extensive fabrication skills. I can't give you an exact cost as they're still working out the pricing details, but what they charged me is quite reasonable. Just wanted to let folks know that there's a commercial option out there for A-Bodies. I've included some pictures for your viewing pleasure.
Click to expand...


That looks pretty nice especially after I spend about 40 hours making one for my '69 Barracuda. From your pics I guess you must completely remove the center portion of the upper cross member making it necessary to remove the torsion bars, etc. For someone who plans to get their car down to that point it's a very good solution as long as the price is reasonable. Of course reasonable is, "in the eye of the beholder"!!!
GOOD LUCK!!!

treblig
 
I can't see clearly in the pics, but if the whole upper mount is welded to the floor (factory only had tack welds) it would transfer a good bit of the flexing to the body. That would help considerably. The new upper mount would also have to be fully welded to the factory cross member, I know it's welded on three sides but I can't see how you would weld on top??/
The basic design looks good, it's just a matter of transferring the "twisting" motion to a solid part of the body/frame.

treblig
 
@Mopar Tim - FYI, I'm running an RMS Alterktion front suspension, so I don't care much about forces from the torsion bars anymore. That being said, the torsion bars actually affix to the rear of the stock crossmember (i.e. the hex portion is to the rear). If you look at the last pic pretty closely and draw a mental vertical line through the rear torsion bar attachment point, the angles suddenly don't seem that extreme (at least to me).

@Treblig - Yeah, I could see someone putting a ton of work into this type of mount. Its tough to tell from the pic, but the entire mount is built like a brick $hit house and is seam welded to the floor all the way around. With this mount, a set of frame connectors, and torque boxes, I'm not worried about rigidity.

If you guys want to check out high res versions of these pics, you can see them here:

http://uscartool.com/body-in-white/jeffs-67-dart
 
With that lower section closing it off, the torsion bar forces look to be well managed in the middle area and spread well there. (Assuming the material thickness is reasonable; it looks thicker than the original.) Transferring force to the angles per se will not be any issue if they are well welded ; you could have a piece welded at 90 degrees to the remaining portion of the crossmember and still transfer the force well. The t-bar forces are trying to pull the central section of the crossmember downward so the main loading on the floor will be on those angled sections; it might be better to have their sides spread wider, and flanged for a better weld to the floor. But at least their length helps spread that load along the floor.

That trans pan is going to catch hell! #-o
 
nm9stheham said:
Anyone doing this who retains the T-bars WILL care....so it is a fair question.
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I agree....that makes a big difference. From the low hanging trans pan I figured it was a drag car otherwise you'll have some "bottoming out" issues. But, back to the subject, if a guy/girl is running torsion bars and they seam weld the new upper cross member to the body it should help to transfer some of the twisting motion. Since the trans pan hangs so low and if you run torsion bars it would be pretty easy to make a belly loop from one side of the sectioned cross member to the other side reestablishing the connection between both sides...but that's another subject altogether???
I still think it's good concept, you just have to mitigate the issues that will arise depending on your application!!



I retained the great majority of my upper cross member then reinforced it (welded) with 1/8" plate on the top side:
Treblig
 

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A couple of additional pictures that you might find helpful...
 

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Doesn't look like I can upload high resolution pics. Guess you'll have to go directly to the US Car Tool site if you want to see them full screen.
 
Dart Vadr said:
Doesn't look like I can upload high resolution pics. Guess you'll have to go directly to the US Car Tool site if you want to see them full screen.
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I went to the website but there were so many pictures there I gave up after looking for about 10 minutes. I was looking for pics of the seam welds and also to see if you were able to weld the new trans mount on the top side (where the floor pan covers the trans mount). I think what "nm9stheham" was alluding to was that if you do start selling these (which I think would be great) you'll need to let the buyers know that you used this new mount on a car that doesn't have torsion bars. This way, if the buyer is using torsion bars, he/she knows that there might be an issue with "twisting". I'm not saying that there will "absolutely" be an issue but I didn't design the new mount and haven't seen it first hand so I can't say.

Treblig
 
@Treblig - If you want to exchange e-mail addresses via PM, I'd be happy to shoot you the high resolution pics that I have.
 
Dart Vadr said:
Doesn't look like I can upload high resolution pics. Guess you'll have to go directly to the US Car Tool site if you want to see them full screen.
Click to expand...

The problem is this website. If you can host them somewhere else, and then post them here, they will show as you want. Please don't, however post huge giant photos much over 800x pixels

However, you are going to have to "tell us" where we are going over at US Car Tool

ALSO I AM CONFUSED

Is it 2004R or 200R4?
 
The bottom pic in post #1 is a very good view of the offset needed.
My inquiring mind wants to know... Would just moving the entire cross member and installing B-body torsion bars accomplish the same ? I don't know how much longer the B-body torsion bars are.
 
67Dart273 said:
The problem is this website. If you can host them somewhere else, and then post them here, they will show as you want. Please don't, however post huge giant photos much over 800x pixels

However, you are going to have to "tell us" where we are going over at US Car Tool

ALSO I AM CONFUSED

Is it 2004R or 200R4?
Click to expand...


For some reason GM calls the smaller transmission the "2004R" but the larger one is known as the "700R4".

Treblig
 
Looks way stronger than it came from the factory, especially with all the seams welded up. Those running torsion bars will have a more ridged platform than a stock tack-welded chassis.

You are going to love the overdrive and the lower 1st gear. I like the bellhousing adapter too. Is this the Extreme Automatics 200R4? Level 2 or 3?Lonnie sure builds a great transmission!

I have the same pan on mine, and my exhaust sits at virtually the same level as my transmission pan, and I do have to go slow over high speed bumps or my collectors will scrape, but have yet to have an issue with either of my oil or trans pans. I don't like my cars slammed to the ground, as they are open road cars and need clearance under the car.

I have to run Nitto 555 Drag Radials to hook up my car on the street. They are great all around tires too.
 

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If US Car Tool is listening, I'm in, depending on price.
 
Looks way stronger than it came from the factory, especially with all the seams welded up. Those running torsion bars will have a more ridged platform than a stock tack-welded chassis.
Click to expand...

Its not the tack welds that support the torsion bars, its the bolt in cross member. the cross member ties the two sides together very nicely. A nice bit of engineering on Mopars part. :burnout:MT
 
jbc426 said:
I have the same pan on mine, and my exhaust sits at virtually the same level as my transmission pan, and I do have to go slow over high speed bumps or my collectors will scrape, but have yet to have an issue with either of my oil or trans pans. I don't like my cars slammed to the ground, as they are open road cars and need clearance under the car.
Click to expand...
Coming from the rally perspective, I am probably more hyper about ground clearance than anyone else here. I've busted/ripped off multiple exhaust bits and pieces and busted oil pans wide open. So you probably should take my comments on ground clearance with a grain of salt, unless you are planning on running the Baja 1000 LOL
 
Mopar Tim said:
Its not the tack welds that support the torsion bars, its the bolt in cross member. the cross member ties the two sides together very nicely. A nice bit of engineering on Mopars part. :burnout:MT
Click to expand...

I agree...the tack welds are there to hold the body (just above the tunnel) to the frame (cross member). The tack welds offer little or no resistance to the torsional stresses caused by the bars. But seam welding the new (US Car Tool) transmission mount to the floor should replace some of the strength lost by removing the original tunnel cross member. I honestly don't know how much the seam weld will offset the structural loss of the cross member center section??? The problem (if there is one??) is that the new trans mount isn't on the same line (axis) with the original cross member L & R pieces so the stress along the axis of the original cross member will still try to twist the L & R pieces. I guess you have to be an engineer to calculate the stresses and how they transfer through the original cross member and through the seam welded trans mount.
I guess if you could imagine a long arched bridge crossing a wide river. This bridge arches up and over the river but in the middle (halfway across the river) the bridge take a dogleg to the left then continues for a while then a dogleg to the right to get in line with the other side. It would look pretty scary but I have no idea how much load it could carry???
Still think it's a good idea, depending on price.


treblig
 
Also, as far as transferring forces from the torsion bar sockets goes, just take a gander to the outside of each of those sockets. Considerable resistance to rotation there will be kept in check by the frame connectors.
 
Mopar Tim said:
Its not the tack welds that support the torsion bars, its the bolt in cross member. the cross member ties the two sides together very nicely. A nice bit of engineering on Mopars part. :burnout:MT
Click to expand...
The bolt in part and the arched part work together as an assembly (which is maybe what you are saying), and with the floor. The tack welds tie the floor in with the other 2 parts, both for some strength and for stability.

In this new case, the angled bits transfer force partly to the floor immediately above them and also to the tunnel part and cross member. The floor stabilizes the whole thing in a horizontal plane and does add some strength. The design is actually the same except for the angles. That is why the quality of the welds at the angles are important.
 
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