Specs for a universal trans crossmember

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Cheepy79
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Joined: Sat May 22, 2021 6:04 am

Specs for a universal trans crossmember

Post by Cheepy79 »

Hello all, I have searched the internet looking for a crossmember to fit my 79 chief. With no luck, I’m looking at universal crossmembers. Can someone help me with the specs/what may fit. Without the old one I’m lost to know what the drop may be or what other measurements I may need. Any help would be appreciated. My project is stalled until I can find a replacement.

TIA!!
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fulsizjeep
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Re: Specs for a universal trans crossmember

Post by fulsizjeep »

I have a good condition cross member I was going to scrap. I imagine shipping could be pricy depending on where are you located. If you put location in your profile, people won't have to ask.

Say, I searched your posts and you have not placed a wanted ad for the cross member but have responded to a few for sale ads. Want ads work.
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twisted frame
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Re: Specs for a universal trans crossmember

Post by twisted frame »

Sourcing a used one from a member like fulsizjeep is your best bet. If you go with a universal one, I think you would need to measure the width between the inside of each frame rail where the old, stock trans crossmember used to exist. I'm unaware of one that will just drop-in without any modification or at least minor trimming/grinding.
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tgreese
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Re: Specs for a universal trans crossmember

Post by tgreese »

I needed a replacement cross member for my '82 J20. Description of the process is here - https://www.fsjnetwork.com/forum/viewto ... 20#p119366

Finding another was easy once I let the community know what I needed. Looking at the parts book, all '76-79 wagons and J-trucks use the same cross member, Jeep PN 8126801, though the PN won't help you. I expect that other years will work too, and will have only minor differences like an additional hole or two.

Suggest you include your location and year/model equipment in every post. There are places to put that in your profile.

Note that there are brackets and insulators and such that attach to the cross member and support the tail end. These change from application to application, with different parts for different engines, transmissions and chassis. The girder that goes between the frame rails does not change.

Image
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threepiece
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Re: Specs for a universal trans crossmember

Post by threepiece »

tgreese wrote: Sun Jun 06, 2021 1:14 pm I needed a replacement cross member for my '82 J20. Description of the process is here - https://www.fsjnetwork.com/forum/viewto ... 20#p119366

Looking at the parts book, all '76-79 wagons and J-trucks use the same cross member, Jeep PN 8126801, though the PN won't help you. I expect that other years will work too, and will have only minor differences like an additional hole or two.

Note that there are brackets and insulators and such that attach to the cross member and support the tail end. These change from application to application, with different parts for different engines, transmissions and chassis. The girder that goes between the frame rails does not change.

Image
To avoid misunderstanding there is a change to the shape of the “Girder” portion of the crossmember that occurred in 1980. The purpose seems to be to provide clearance for the front transfer case output. The picture in your post shows the change. The early girder has a more pronounced recessed area on the opposite side to accompany the Dana and Borg Warner transfer cases.

In addition the location of the girder in the frame changed in 1980 as well. There is a slight change to the location of the holes in the later frames.
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