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2wd to 4wd conversion

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Bullnosefan95

2wd to 4wd conversion

Hello all, I am looking to convert my 86 f250 to 4wd, I plan to keep the twin I beam suspension for ease and because I don’t do a lot of Off roading. Mostly for when I hit the snow during some months of the year or if I go camping in the mountains. I found a twin I beam diesel rated 4x4 set online from a private seller and want to be sure that it should basically just bolt up and will be good? Obviously have to do t-case and so on but I want to be sure I’ll be good on the front end. Thanks.

1986 F-250 Diesel
7.3 IDI (It was a conversion due to the 6.9 being bad in it originally)
2WD
C6 Auto
4.10 Rear

salans7

Re: 2wd to 4wd conversion

It will NOT bolt up. The 4x2 frame is different from the 4x4 frame on a 3/4 ton and one ton truck. The pivot brackets are in different places, the frame isn't set up for the leaf springs, etc. I crossed this road with my F350, but ultimately I went with a straight axle and had to do some fab work to modify the frame to work with leaf springs.

Gary Lewis

Re: 2wd to 4wd conversion

Administrator

Thanks, Shaun.

There's more info on the options discussed in the New Member New Build, Looking For Directions thread. And in Converting 87-96 Trucks To Bullnoses. And Am I Asking For Trouble Attempting A 4wd Swap On A 2wd F250?

Those threads should help you understand what the problems and options are. Let us know what you decide, please.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Gary Lewis

Re: 2wd to 4wd conversion

Administrator

Oh, and I should have said I really do NOT like the leaf-sprung F250 4wd suspension. Big Blue, which had new springs up front, rode really poorly. REALLY poorly. As in, you made sure your mouth was closed before hitting bumps for fear your teeth would chip hitting each other.

The issue is that the swinging TTB's are trying to twist the springs as well as compress them. It just doesn't work well at all. Coil-sprung TTB's work really well, and leaf-sprung solid axles work well. But not so leaf-sprung TTB's.

As a comparison, Big Blue's original front suspension had about 2" of travel from full droop to full compression. But with the D50, RSK, SD spring combo it now has 7 1/2" of travel. And that makes a HUGE difference in the ride.

I'm not trying to talk you out of the 4wd conversion, but I do think you should know what you are going to get with all the cost and effort.

Gary, AKA "Gary fellow": Profile

Bullnosefan95

Re: 2wd to 4wd conversion

Ok it has definitely opened my eyes to know what I should be doing. I wanted to get out of doing a D60 due to cost but nothing against saving money for it

1986 F-250 Diesel
7.3 IDI (It was a conversion due to the 6.9 being bad in it originally)
2WD
C6 Auto
4.10 Rear

Gary Lewis

Re: 2wd to 4wd conversion

Administrator

If an F250 TTB was a bolt-in and cheap the bad ride might be acceptable. But it is far from bolt-in and not cheap. So, to me, that is three strikes against it.

Sorry to rain on your parade. But far better to know up front.

Gary, AKA "Gary fellow": Profile

salans7

Re: 2wd to 4wd conversion

I struggled hard as well when it came to what options to go. But the more I researched, the more I realized that the straight axle was the better way to go.

Bullnosefan95

Re: 2wd to 4wd conversion

I think the hardest obstacle I have to face is the wife. She firmly believes the truck belongs at pick n pull, even though I tell her it’s never going to happen haha.

1986 F-250 Diesel
7.3 IDI (It was a conversion due to the 6.9 being bad in it originally)
2WD
C6 Auto
4.10 Rear

Gary Lewis

Re: 2wd to 4wd conversion

Administrator

Hey, many of my trucks have been to the pick & pull, and they’ve come home loaded. Good idea!

Gary, AKA "Gary fellow": Profile

salans7

Re: 2wd to 4wd conversion

Gary Lewis wrote

Hey, many of my trucks have been to the pick & pull, and they’ve come home loaded. Good idea!

I have parts from the pick and pull on all of my trucks. Both my old F150 and my current F350 have been primarily built out of parts from the pick and pull, or from parts trucks I bought that should have been at the pick and pull.

salans7

Re: 2wd to 4wd conversion

In reply to this post by Bullnosefan95

Hop on Facebook Marketplace and see if you can find yourself a set of Super Duty axles. 1999-2004 were leaf sprung like ours. The only big differences are the perches have a different spacing, and they use unit bearing assemblies instead of traditional cone and race like the older D60's. They're a little cheaper than the older style axles ($600-800 for a set where I live) and they're becoming a popular swap on these trucks. Keep in mind though that there are D50 and D60 axles in the Super Duty trucks. Nothing wrong with the D50, but you may find some of the internal parts are different.

Sky's Off Road Design offers parts to make them work with the older trucks. Their kits aren't technically bolt on for a 4x2 truck, but I and a few other people have made them work on our 4x2 trucks with a little fabrication and they work just fine.

https://www.skysoffroaddesign.com/