2 wheel drive to 4 wheel drive
 

Ok guys just joined but have been reading threads for a while. I have a 72 f100 with a 302. It is currently a 2wd and im thinking of going 4wd. Now I've read a couple threads that are on the same subject. But wat I want to do is put 3/4 ton axles and transfer case. With a 4 in suspension lift and probably 35s. And no im not going to swap the body onto a 4x4 frame. And for my front suspension I was thinking a leaf spring set up. My main concern is wat axles and transfer case should I use. And im trying to do it on somewhat of a budget.

Whichever direction you go, the front crossmember will have to be relocated or clearanced. Your welding skills better be up to snuff or you'll be in over your head real quick.

Option 1. Driver-side Dana 60s and a divorced NP205 or NP203/205 doubler.

Option 2. Passenger-side Chevy/Dodge Dana 60 with a divorced Dana 205 (sourced from a Chevy or Dodge).

My welding skills are decent. But there are ppl in my family that can weld.

Alrightee then... My recommended options are posted. I'm sure others will chime in....

Meanwhile, how about this approach for inspiration??? 1979 Ford F-150 - Driveline Conversion - 4Wheel & Off-Road Magazine

Friend, I see wisdom in your user name, but wonder where it is in what you are wanting to do? What is it that you are so in love with in non-seen parts that you want to put yourself through.

You not only have to swap the front axle but the matching rear axle ratio also. They have to be a matching pair.

Placing your seen parts onto a 250 4wd chassis will put you out light years ahead.

But IF ya gotta bleed, please do so.

I only want to you to think about what I wrote, not be offended by it. :-drink



John :-X06

Well that’s my plan. I’m tryin to find a 80s f250 with a blown motor or tranny so I can have matching axles and transfer case. But the main reason for doing it is for the challenge. I love challenges especially when it comes to cars and trucks. I’m currently enrolled in an automotive technology program and they are teaching me the basics. But I want to do custom stuff. And learn how to do things like this. My grandpa has been working on cars years and years before I was born and he has helped me with getting my truck to where it’s at now. And I want to follow in his foot steps. He works on classic and modern cars (mostly classics) and I try to help him as much as I can. He has a 50 Willys that has gone from stock 2 wd to 4 wd and now its chopped 6 in. and is tubbed with a big block. And that’s why I want to follow in his foot steps, cuz of everything he has done. I have learned a lot from him. And I’ve been planning on good bracing for the frame and everything like that. That’s why I want to do it.

Well the beginning of your problems come in right at the frame. While grandpa might have done the 2WD to 4WD conversion on a Willy's assuming without a frame swap do you know if Willy's used the same frame for both? You are talking about swapping out a straight axle for a straight axle. No big deal. You on the other hand are going to try to make a 4WD out of a 2WD. They are different frames. Grandpa's conversion was a piece of cake compared to what you are proposing. Unless you use an incredibly high lift you will at least need to heavily modify the front crossmember. The 4x4s had the crossmember out near the core support. 2WDs have a crossmember right under the engine and it has a very deep drop in it. Read this as no clearance for your pig on the front axle.

You really are way better off swapping the body onto a F250 4x4 chassis if that be your desire. Of course at that point why not just buy a 4x4 and work on it? Are you aware that '80's generation trucks are IFS 4x4s? I know the 150s are not positive about the 250s but if memory serves me correct they are as well. Is that your desire? An attempt at putting a IFS 4x4 under the truck using the original crossmember?

No that is not my desire. And my grandpa did use the same frame for both. And I do know that the front crosmember is in the way. I have already planned to fix that. And second I dont want ifs I think its crap and no the solid front axle would be better for my needs. And I want to go thru the experience of the whole build. It will give me experience on building cross members and mounts.

Your grandpa used the same frame because the suspensions are the same for a 2WD & 4WD back then. They were both solid straight axle front suspensions. There was a truck thread running around with a guy converting a 350 from 2WD to 4WD. Last I read he still hadn't figured out how to get the front crossmember in. He had cut it into pieces & I believe the recommendation was to find a way to spread the frame rails. Just so you know the steering box mounts out front on a 4x4. Up close to the cab on a 2WD. Don't know if he ever got it in or not. He was headstrong about doing it his way too. You do know the 250 frame is also different from the 100 right? Using 250 springs and axles will gain you nothing as the frame is still light weight compared to a 250. Just pointing out some of the obvious roadblocks you are going to run into.

I put my 68 F100 on a 78 F150 chassis. Had to cut 2" out of frame behind cab to get correct wheelbase and add bed mounts to the frame (tapered vs parallel). Was really pretty easy. I have a few pictures in my album.

I admire your desire to fab up your own conversion, I was going through the same plans when I decided to convert my 2wd F250 to 4x4. Even found a complete drive train with a front axle. The more I planned the more I realized how different every thing was. Lots of frame cross members are different and located in different places. Cab mounts were outside the frame so the transfer case support cross member could be added, etc. etc.

Then I got lucky and found an entire rolling 4x4 71 chassis for $300.00, the only thing missing was the body and some maintenance of an engine that was poorly maintained by the volunteer firemen. The difference was I wanted a 4x4 worse than the experience of redesigning the entire frame and suspension. I did have to undo some after market modifications that were done to make the 4x4 chassis a brush fire truck, like removing the chassis mount water pump and gear drive systems. Still have the extreme stiff suspension that chips my teeth when I hit a pebble on the highway.

After getting the body off the perfectly good 2wd chassis, my brain started thinking about converting the 2wd chassis to a lifted pre-runner. That would have been fun on the dunes, but full time job and new wife changed my priorities. Focused on finishing the one project and staying married.

Good luck with your project and don't be so set in your plans that you don't stay open to alternatives. You never know what direction you will end up going depending on the options you are presented.