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Old 01-03-2009, 12:44 AM
MoparFan's Avatar
MoparFan MoparFan is offline
Join Date: Jan 02, 2009
Location: Charles City, IA 50616
Posts: 35
Question FNG... Need Some Help Please - Rear Cross Member

Hey guys... first I want to say that I'm looking forward to hanging out in here and getting back into Jeeps (had 76 Cherokee Chief Wide-Track back quite a while ago). You guys seem to be a fountain of information and so far seems to be the best Jeep forum I've come across.

Anyways... I've found a 1978 Wagoneer for sale on here that I'm hopefully going to be the new owner of next week sometime if it doesn't get sold before I get the cash together.

But I have a few questions and I can't seem to find an answers to them (I've searched the forums and it's probably looking me right in the face and I've just not seen it).

Here's the situation though... The rear cross member on it is bad. I'm wondering how much of an integral part of the Jeep it is? Also, how difficult is it to fix/change? I've never had to deal with cross member problems before. And yes, this is going to be a really stupid question... but what purpose does the rear cross member serve?

The reason I'm asking is I'm wondering if towing a car trailer with an old 74 Dodge truck loaded on it is going to be a problem or if I need to get that fixed before even considering the trailer situation.

Any help you guys can give me will be greatly appreciated!

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Old 01-03-2009, 10:14 AM
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Chevelleguy Chevelleguy is offline
Join Date: Jul 20, 2003
Location: Hughes Springs, TX
Posts: 5,572
The rear crossmember is held in by large rivets. They can be cut out and replaced with bolts. The purpose of the crossmembers is to tie the frame rails together. The more crossmembers, the stiffer the frame.

I'm not sure I would want to haul a full size Dodge truck with an FSJ in the first place. Maybe a short distance with no freeway driving. These rigs of ours are technically mid size SUV's, same size as a Ford Explorer, and the brakes aren't great to start with. Then you want to throw another 7000lbs of truck and trailer behind it.
David "If all else fails, read the instructions."
83 Wag Lt,BJ's 6"lift,360/727/Pinned229,D44/trac-lok,AMC20/lock-right,35/12.50 Baja MTZ,Pro-Jection EFI.
10$ NP229 fix
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Old 01-03-2009, 10:25 AM
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J4GRAND J4GRAND is offline
J4000 Restoration Specialist
Join Date: Apr 09, 2000
Location: Crawfordsville, IN USA
Posts: 5,937
I replaced the rear xmember on my J4000 with a piece of 1/4" thick steel angle iron bent into a C channel. The height at the rear of the frame is something strange (like 5" or something) and a 6" C channel is too large to fit without using spacers. I took the angle iron to a metal fabricator and they were able to bend it to the proper dimension.
Patrick V.
73 J4000 "The $LUT" 360 V8 bored .040 over Edelbrock 2131 1407 4V carb K8600 cam Dual Flowmaster 40 mufflers TH400 QT 3.73 Dana 44s
78 Cherokee Chief WT "Old Blue" 360 V8 4V TH400 QT RIP
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Old 01-03-2009, 11:18 AM
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fulsizjeep fulsizjeep is offline
Señor Jackhead
Join Date: Aug 21, 2002
Location: Jubilee Jeeps.SWCO
Posts: 22,491

The bumper also bolts to the cross member on Wags and Cherks. Not so sure on the trucks but I believe they attached to the frame rails. I haven't looked in a while but don't the 2 rear body mounts for the Wags and Cherks fit on rear cross member?

Might want to look at this:
Says 79 and up but I thought that 74 and up were the same.
Ran when parked.
88 GW, 401/727/208, 5" lift, D44s/4.10s/locked up, 35s with a few Evil Twin & TT's Fabworks mods
76 401 Wag, 77 401 Wag, 77 401 J20
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Old 01-03-2009, 11:30 AM
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Tornado230 Tornado230 is offline
350 Buick
Join Date: Sep 14, 2008
Location: Fleetwood, PA
Posts: 1,488
The rear cross member has a lot riding on it.
I bought one many years ago that had a 2 x 4 jammed in the back on top of what was left of the crossmember. Did the job, but the body was dropped enough that the back doors would not open.
I know of 2 situations where the rear cross member really came into play.
A friend of mine was sitting waiting to turn left when a pickup used him for brakes. Everything was in good shape in the rear. If the crossmember would not have been up to snuff, the truck would have been against the back of the back seat.
Also, not quite the same, but I saw the aftermath of truck VS CJ7.
The only thing that kept the body from coming off the frame was the large body mount in the front.
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Old 01-03-2009, 12:52 PM
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MoparFan MoparFan is offline
Join Date: Jan 02, 2009
Location: Charles City, IA 50616
Posts: 35
I just want to say thanks to all of you that responded! I have a lot more info now and that helps a lot!

I was sort of figuring the worst when it came to the necessity of the rear cross member... but was hoping it wasn't too much of an integral part.

As for the towing part... I thought the Waggy had a towing capacity of about 5,000lbs but wasn't completely sure... though it sounds like I was probably pretty close on my guess. Was hoping I could do a 150 mile trip with a trailer/truck though (was planning on back roads and nice and easy if I did) but that sounds like a no-go.

Fulsiz... thanks for the link... I was reading the page and yup... it will work... here is what is says "Will fit 1976-1978 Wagoneers and Cherokees also but some holes need to be drilled for the bumper mounts" so just a little mod needed on that.

Again, thanks everyone for the help... I really appreciate it!

Have a great day!
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