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4L80E 2wd '99 crossmember modification.

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Old 07-21-2005, 09:56 PM
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Default 4L80E 2wd '99 crossmember modification.

Ok, here are some pictures of my transmission crossmember and what it takes to modify it for a 4L80E swap. Evidently this is a '99 crossmember and the '00+ use a different shorter crossmember. BTW, my truck is a 2000 so it must've been made late in '99 or something and got sold as a 2000.

The picture below shows my crossmember on top and the 2000+ style crossmember below. The one on the bottom is actually the modified version that I got with the Speed Engineering kit. It was no fault of theirs though, there was no way to know my crossmember was different until the other one got here. The left as your looking at the picture is the driver side.



Sean at Speed Engineering took both crossmember back and made a bracket for my stock one to work but, do to some miscommunication on my part the bracket just wouldn't work. Instead of shipping the crossmember back I decided to just modify it once I had the trans in the truck and bolted up.

So today I finally got the trans in and realized right away the stock transmission mount on the crossmember would have to come off. It came off quick just buzzing the welds with a grinder.

I put the crossmember in place and held the mount up on it but, on the backside instead of the front like it is stock. It looked like it would work fine like that so I tacked it in place. With everything solid you could see the transmission mount hole needed to be slotted quite a bit so I marked it and took the crossmember down. Got the hole slotted and the mount fully welded. Put it back up and everything was perfect.

Here is a picture of the finished crossmember.



So if you have a crossmember like the one I have all you have to do is grind the mount off and flip it over to the other side along with slotting the mount hole. I'm not sure if the transmission is up as high as it should be but, that would be easy to fix with a few spacers/washers.
Old 07-21-2005, 10:43 PM
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Nice fab work. Sounds like the 4l80E is longer but mounts at same height?
Old 07-21-2005, 10:52 PM
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The 4L80E is just a little longer than the 60E but, the mount is on the tailhousing instead of the actual trans case so it's spaced quite a bit further back.

I am going to measure the mount height sometime tomorrow or this weekend to check. It was not something I thought about until after getting everything in. LOL.

Thanks for the props on the fab work. I made the picture smaller so you couldn't see up close.
Old 07-22-2005, 09:58 PM
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That is exactly what I did to my tranny crossmember. I paid a metal shop $30.00 to cut the mounting plate off turn it around and weld it to the back side of the mount. Cheap and it works.
Old 03-04-2008, 09:53 PM
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Im a lucky 2000 owner that has that crossmemeber..
If all you did was cut it off and flip it.. why did you have to slot the hole??
Old 03-04-2008, 10:09 PM
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The hole should be slotted from the factory. At least mine was.
Old 03-04-2008, 10:22 PM
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Originally Posted by quicksilverado
The hole should be slotted from the factory. At least mine was.
thats why i was asking... mine is slotted..
Old 03-05-2008, 06:05 AM
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Holy OLD THREAD Batman!!

Did you guys use a backhoe to dig this up?
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