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Transmission crossmember ?


DragCat

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Just an update in case someone comes across this thread in a search mode. Right now i'm not doing anything explanation below.

I contacted G Force this am because everything I read said their holes were 53 5/8" inch's apart, and even their website description said to use a 1/2" drill bit on the existing holes to fit. I measured mine yesterday (center of bolt to center of bolt) and its 54 1/2". So with all that information in my question their reply was drilling the holes was NOT recommended but if I was any good at fab work (welding and such) they would send me a procedure.

Well unlike Joe and others on the forum I have NO fab work skills lol. And no offense to anyone who's done this and offered their experience to me. Since its not "mission critical" for me to continue on my project I'll revisit it once i'm back on the road. I'm just not ready to drop $300 on a part that the manufacturer doesn't recommend doing modifications to make work. 

Thanks again to everyone 

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Why is the dimension that wide would be my question? I'd maybe look at one of the frame dimension diagrams here and start measuring to see if something is tweaked a bit. Also look to see if someone prior bent the side framerails by jacking it up in the wrong spots. They may have rolled that mounting surface out & caused it to be off.

Mine was rolled up a bit from that very situation, and I had to bend the mounting hole area back so it was parallel to the ground.

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12 hours ago, jft69z said:

Why is the dimension that wide would be my question? I'd maybe look at one of the frame dimension diagrams here and start measuring to see if something is tweaked a bit. Also look to see if someone prior bent the side framerails by jacking it up in the wrong spots. They may have rolled that mounting surface out & caused it to be off.

Mine was rolled up a bit from that very situation, and I had to bend the mounting hole area back so it was parallel to the ground.

All good points Joe, and I am going to have to dig in deeper to it. I just wanted to update the thread that my timeline  got kicked out a tad and where I was 

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On 3/16/2020 at 7:26 PM, jft69z said:

Why is the dimension that wide would be my question? I'd maybe look at one of the frame dimension diagrams here and start measuring to see if something is tweaked a bit. Also look to see if someone prior bent the side framerails by jacking it up in the wrong spots. They may have rolled that mounting surface out & caused it to be off.

Mine was rolled up a bit from that very situation, and I had to bend the mounting hole area back so it was parallel to the ground.

Ok, all I could find in my shop manuals from what i'm reading adds up to max 53" so 53 5/8" on the x-member would be to big. 

 

Frame.png

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That 53" you're seeing is for the body mount holes (26 1/2" x 2) I think. The crossmember bolt holes are a bit outboard from that, at least on my car. My crossmember holes are approx. 53 1/2" apart, definitely not in line with the upper body mount hole that is towards the center of the side frame rail.

I'm going to ask something stupid here, and please don't be offended (because I've done this very thing before). Sometimes when I use a metal tape measure, I'll start at the 1" mark, so I don't get involved with the metal hook on the end of the tape. I've occasionally forgot to subtract the 1" from the total measurement, scratch my head a few and then laugh at what I did. Any possibility that may have happened, because it would then put you right in the ballpark.

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2 hours ago, jft69z said:

That 53" you're seeing is for the body mount holes (26 1/2" x 2) I think. The crossmember bolt holes are a bit outboard from that, at least on my car. My crossmember holes are approx. 53 1/2" apart, definitely not in line with the upper body mount hole that is towards the center of the side frame rail.

I'm going to ask something stupid here, and please don't be offended (because I've done this very thing before). Sometimes when I use a metal tape measure, I'll start at the 1" mark, so I don't get involved with the metal hook on the end of the tape. I've occasionally forgot to subtract the 1" from the total measurement, scratch my head a few and then laugh at what I did. Any possibility that may have happened, because it would then put you right in the ballpark.

Hey Joe, me take offense ? lol. No worries But no I taped the metal hook to the middle of the bolt holding the x-member. I was surprised at the number so I started with the forward bolt and remeasured the rearward bolt. Both 54 1/2". Maybe I have a station wagon frame ( body mount spec around 28") laughing. Very strange I'm that far off. Oh well going to need further investigation. 

And yea I've had many a laugh at myself working on cars. I'd rather someone point out whats obvious to them or slips from their experience. Thats why I joined this forum and ask a bunch of questions. 

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Tom (MC1of80) posted this pic a while back, might be a good time to use these diagrams and start measuring a few spots to see what's going on. The diagonal measurements are good to see if the frame is square too.

If you look down the length of the side rails, does it look straight, or bowed out a bit? I put a 4' straightedge along the side of mine when I rolled the bent bottom parts up, just to make sure it was straight along the sides. Might be worth a look.

IMG_20191209_122419.jpg.fd8beb9ced384f5d37e2dd37c3f2f55e.jpg

MC frame-1 .JPG

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Thanks, I'll work off that sheet. I just measured from the top in the engine compartment the forward point and its 39" so its a start in the right direction lol. It looks like i'm going to have to do the others from the bottom so I'll get on that. 

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Tom's diagram is the bottom view & the other one looks like a top view of the frame.

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Looks like one that would have been used in a collision shop environment, for pulling frames back into shape.

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Ok so I was able to get under the car yesterday, just remember i'm working by myself so I had to put a socket on the body mount bolt, use an extension and tape the ruler to that. Then I had to tape them to the frame so there may be some + or - variables lol. The top measurements are from Tom's sheet the bottom are mine. Note 1 I couldn't do the one because the fuel tank is in the way so it would not be point to point. Note 2 on the rear I didn't see a body mount so I measured from the two holes about 6 inches from the back. Note 3 I wasn't sure on the engine x-member which hole to use. Note 4 the trans x-member 1st bolt forward of the center body mount is 4", and the spread between the x-member bolts center to center is 4 1/2". The weird thing is the center body mount on Tom's spec is 53" and mine is dead on to that. 

1Frame.jpeg

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On 3/16/2020 at 5:22 PM, DragCat said:

Just an update in case someone comes across this thread in a search mode. Right now i'm not doing anything explanation below.

I contacted G Force this am because everything I read said their holes were 53 5/8" inch's apart, and even their website description said to use a 1/2" drill bit on the existing holes to fit. I measured mine yesterday (center of bolt to center of bolt) and its 54 1/2". So with all that information in my question their reply was drilling the holes was NOT recommended but if I was any good at fab work (welding and such) they would send me a procedure.

Well unlike Joe and others on the forum I have NO fab work skills lol. And no offense to anyone who's done this and offered their experience to me. Since its not "mission critical" for me to continue on my project I'll revisit it once i'm back on the road. I'm just not ready to drop $300 on a part that the manufacturer doesn't recommend doing modifications to make work. 

Thanks again to everyone 

Mark, I have to stop you here. You do NOT have any holes to modify. Your frame holes are for the rubber insulators, not a Chevelle that you are upgrading. You are drilling new holes. And I believe the G-Force uses 7/16 hardware, not 3/8". 

 

That being said, drop the old crossmember out, put the 80 pound G-Force in. Bolt the mount on, center it best you can, and mark it with a fatty Sharpie on the frame.  Drill the new holes with a step bit from Harbor Freight (like $23 for 3) and go to town. 

 

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On 3/23/2020 at 12:26 PM, Andy's Auto said:

Mark, I have to stop you here. You do NOT have any holes to modify. Your frame holes are for the rubber insulators, not a Chevelle that you are upgrading. You are drilling new holes. And I believe the G-Force uses 7/16 hardware, not 3/8". 

 

That being said, drop the old crossmember out, put the 80 pound G-Force in. Bolt the mount on, center it best you can, and mark it with a fatty Sharpie on the frame.  Drill the new holes with a step bit from Harbor Freight (like $23 for 3) and go to town. 

 

Hey Andy, sorry for the delay, i'm having sketchy computer issues on the forums again. 

The reason for putting the brakes on the upgrade was the difference on the measurement mounting holes. GForce and the other similar are very specific on the mounting hole measurements and i'm almost an inch off on my existing and thats why I took measurements from the body mounts supplied. I should be dropping the crate in and putting the trans back in this week (fingers crossed) so i'll get back to this then. 

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