From Frame Rails To Custom 75 Cj5

The way I see it, I have a 2004 4WD dakota original owner with 75,000 miles that runs great with a rusted out frame and body. Just part of the steal would be a 3.7L V6 with 210hp, C205F front axle, 9.5 rear axle, transfer case with electronic 4H 4L N, both drive shafts, front disc brakes, steering rack and column, all gauges, wiring harness and ECU, radiator and fan, mounts, and seats that parlay into the over all picture of the cost. Hate the hassle of junk yards, you never know what you get for the parts I just listed. Why go through all that when I have a matched proven drive train and brand new frame (or I might just start out with new heavy duty CJ5 frame rails)? Believe me, I will make the dakota axles work. They make all kinds of adjustable links and will fab what I can. I don't use Jeep and nice ride in the same sentence I got a lot of spare time another reason for project and the fact when I was a young lad I had a 1975 CJ5 and really liked it. If the end result doesn't work out, what did I really lose? I could tear it down, sell the parts and definitely make back what I put into project, maybe even profit The time wont be wasted because I like working on cars and trucks, but I might be wasted if you know what I mean

 

I don't have a CJ. Starting from CJ frame (maybe just heavy duty CJ5 rails) and tub.

 

Thanks, most reply's are naysayer's. Nice to hear positive input

 

Fun projects!

 

Yeah, the Vmax had a stage 7 kit installed that was hard to keep tuned and had deleted vboost. It was fast as hell but I'm getting to old for that and I like the whole idea of the vboost so converting back to stock except for the Hindle 4into1 header. Swapping the V6 in the Camaro with a LS3 short block.

 

If the end result doesn't work out, what did I really lose? I could tear it down, sell the parts and definitely make back what I put into project, maybe even profit The time wont be wasted because I like working on cars and trucks. Can you explain to me how to post a pic from a Chromebook? I'll try to post from my android, but I like to use Chromebook for forums.

 

The coils didn't work out either. I ended up going back to yj springs.

 

I say go for it. I considered coils for a 72 narrow track Commando and didn't think i could fit it all in using stock width axles without major frame surgery and not even sure had space to the exhaust manifolds if i were to notch frame.
few questions I would be sleeping on.

First, and the answer may just make the decision for me to do or not to do it.
strength of the Dakota front axle, factoring in how much taller tire you planning or will go to at some point.
gearing - is there aftermarket lower ratios available?

Strength of the steering rack and pinion and if lifting suspension will it handle a steeper angle. Or mount it lower trying to retain factory angle. steer shaft may be easier not having to run shaft to front and you can push that front axle forward easy!
OAL needed to fit radiator to rear axle and have a reasonable rear driveshaft - 18 inch is what i use.
I do not recall what trans tcase you planning and am not knowledgeable on Dakota trans t case lengths but i would bet a CJ5 frame and body will need stretching. Get CJ5 running gear dimension and compare.
height of the motor pan to air inlet - will pan need to be real low or notch hood?
In some ways an IFS be easier with not having to allow for front d shaft up down travel clearance.
Maybe plan to widen frame in rear for t case and exhaust.
I currently swapping a 4.3L with matching 4L60E and NP241 into a CJ2a. Couple years planning in my head and on paper. Done it on Commando but that was longer wheelbase. Started a few months ago by having a couple friends over, beer, sawzall, few hours later had the frame in 3 pieces. i needed longer for auto so started with grille location as far forward as possible, added 10 inches to frame at rear of front leaf hangers - gives me 18 inch rear shaft, and widened rear frame 7 inches - that made it line up with my leaf mount width.
Have fiberglass body and planning stretch 3 in hood, 4 at seats, 3 over rear wheel wells. Fiberglass stretch might be easier, cheaper, and quicker than metal. Check out Boatworks guy on youtube for fiberglass tricks.
I similar to you and try to use anything i can from the donor.

Take lots of pics of and measurements of dakota prior to tear down.
And of a running CJ5

Hurry up, i wanna see those coils sitting in there.

Hope it all goes well for ya if you do it.

 

Thanks for the input tiptoptune2. Dakota has 30” tires, CJ will have 33s. The gear ratio is 3.92 which should be fine. Definitely going to have to shorten the rear drive shaft and hopefully can mount the transfer case so as to use the same front driveshaft. The thing I like about the 75 CJ5 is the short wheelbase 84”. Don’t know why I would need to stretch anything. Never seen a radiator mounted on the rear axle. Widening the frame in the rear is something I am toying with, if it really isn't necessary that's 4 less mandrel bends that don’t need to be done. Working on bend worksheet for 2x4 0.188 rectangular wall frame rails right now. I’m definitely doing build.

 

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By OAL radiator to rear axle i talking distance needed for your drivetrain from radiator to rear axle to determine if you will have adequate length rear driveshaft or need to stretch a cj5 frame. For reference, on my 2a current project I moved my grille forward a few inches and pushed rear axle back and still had to add 10 inches to frame length to get 18 inch rear shaft with a 4.3 and 4 speed overdrive auto trans and the shortest sye available that reduced t case by 9 inches. Think the 2a started life at 80 inch wb originally.
For tire/gear comparison i run 32 inch tire with a 4.3L 200ish horsepower and a 3.06 first gear in the auto trans and 4.27 gears and it works good. If anything i would go to 4.56 gears. 3.55 not any too low with a 35 imo. My trans has overdrive so not an issue at 70-75 on the interstate. Although hearing is a bit rough after sitting in a tin can at 70mph.
On my Commando, same frame width as 75 vintage cj5, i had to dogleg frame to fit t case (np241). If i did it again i would widen the frame which would have made for a cleaner exhaust run.
Or you could just go EV. And hell you could probably get a grant, even if you never finish it. I researched a bit and if had spare money would buy a total and give it a go.

 

Instead of the standard 131.38 frame rail, when I have the rails mandrel bent I'll add 6" (radiator clearance and small plow) to the front and 6 " at the rear and cut off if I don't need. I will in no way change wheelbase . Never gonna own a EV

 

Starting out with 2x4 0.188wall rectangular steel mandrel bent rails. For those who need pics first let me upload my bend worksheet to be double checked and critiqued. Donor is a 2004 Dakota 4wd 3.7v6 with 75,000 miles rusted out frame and body. Don’t have access to a 75 CJ. Working on taking measurements now and any help with locations, angle degrees and CLR would be appreciated.

 

To back up tiptoptune2, you're going to need to do more than shorten the driveshaft. The transmission/transfercase assemblies are really long on modern stuff and don't play well with short wheelbase Jeeps. That's why we jump trough all sorts of hurdles fitting transmissions to these things.

For example, here is your 3.7 V6, automatic transmission, and transfercase. It's really long:


And here is an intermedate 84" wheelbase chassis with the longest engine. The front of your 3.7 can't be further forward than the front of this inline six and still be behind the grill. Look at how short and steep that drive shaft already is with the really short transmission/transfercase:


Your drivetrain is about a foot longer than this and you would have not room for a driveshaft with a slip yoke.

You'll also note that the engine is entirely behind the axle unlike the donor Dakota. You'll need to lengthen your front driveshaft for it to work.

To drive the point home further, my TJ Rubicon has a similar length transmission/transfer case to yours:


At 93.6", it has a 10 inch longer wheelbase than a CJ-5 and the rear driveshaft is literally a double cardan and a slip joint with no tubing at all:



Your proposed drivetrain will not work in a 84" wheelbase. You can't just chop the driveshaft. Something will need to be stretched.

 

Have fun.
http://www.earlycj5.com/xf_cj5/index.php?threads/116061/

 

Any progress on this Jeep?

Another option instead of stretching the body/wheelbase is to move the radiator way forward like this:


I'm not a fan of that look.

Stretching to old-school-cool CJ6 length makes for a really easily fitting your drivetrain:


A CJ-7 would be a little tighter but should work too since that sort of drivetrain works in my TJ with the same wheelbase. The you having a V6 vs the original inline six would let you move the engine forward more and get a decent rear driveshaft length:


Stretching to either of those two lengths would allow the dakota drivetrain and would also have off-the-shelf tops available.