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Cab and chassis f350 2wd to 4wd conversion

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WrenchingtheWretched

Cab and chassis f350 2wd to 4wd conversion

Has anyone done a conversion like this? I’m sure it’s out there but all I can find is F150 IFS swaps etc. I’d prefer to go with a SAS if possible.

“Big Yella”
1982 F350 Dually
400ci 6.6l
NP435 4 speed trans
Sawmill lumber flatbed

Gary Lewis

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

From what little I know it isn't easy as the F250/350 2wd frames are different than the 4wd frames. You should read this thread.

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

salans7

Re: Cab and chassis f350 2wd to 4wd conversion

Things that are different (When swapping a 4x2 F250 F350 to 4x4):

-Shock Mounts
-Front Frame Horns
-Sway Bar (If equipped)
-Pitman Arm
-The bolt holes for 4x4 F250 and F350 trucks are NOT present on 4x2 frames and need to be drilled
-Driveshaft (Especially on C&C)
-Transmission
-Transmission crossmember. (F350 4x4 trucks use a different crossmember than F150/F250 4x4)
-C&C trucks use narrower spring packs out back and will need a C&C specific lift block for the rear
-4x2 Automatic trucks don't have the removable plate on the transmission tunnel (Doesn't apply to you)

There may be other things I'm forgetting.

The Cab and Chassis aspect doesn't really make a difference except for the rear lift blocks and the driveshaft (depends on your wheelbase)

ArdWrknTrk

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

'86-'97 F350's (D60 solid axles w/ 8x6.5 hubs) used a front driveshaft w/ double cardan joint at the transfer case output.
They also had a panhard bar that needs a mount on the crossmember.

But (I'd think) the biggest challenge would be boxing the front of a 2wd frame and getting the shackle pockets right.
One option is an RSK like what Gary did with Big Blue.

He worked with SKY Off-road, as they hadn't perfected a kit for this before.
That adventure is well documented in Big Blue's Transformation here on the forum.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

Good points, Jim. But there's a special thread for my Sky's Offroad Design Super Duty RSK Install adventure. You can find bits and pieces of it in Big Blue's Transformation, but the Sky thread has the nitty gritty.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

I should have known!

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

salans7

Re: Cab and chassis f350 2wd to 4wd conversion

Sky's Offroad now offers a frame box kit for 1980-1991 4x2 frames so you can use their 4x4 RSK kits to swap your 4x2 frames to a solid axle. That's something that wasn't available when I did my swap and RSK kit.

Gary Lewis

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

Good to know, Shaun. Thanks!

Gary, AKA "Gary fellow": Profile

WrenchingtheWretched

Re: Cab and chassis f350 2wd to 4wd conversion

I’m also curious which axles, transfer case etc I should look for at the pull yard. I would like to do the conversion but no time soon I plan to part hunt until I have it all then tear it down and knock it out in a few weeks.

“Big Yella”
1982 F350 Dually
400ci 6.6l
NP435 4 speed trans
Sawmill lumber flatbed

ArdWrknTrk

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

What wheelbase is your C&C? What's the R&P ratio?

You're going to want a '86-'97 D60 with the same ratio as your current rear axle
+ the springs, shackles and frame mounts.
The removable floor pan that has provision for a transfer case shifter + boot
Front and rear driveshafts + transmission crossmember.
Front shock towers, pitman arm and panhard bar from a 4wd 350 with solid axle ('86-97)
The 4x4 transmission, tailshaft adapter and transfer case from a 350, because the front output yoke is double cardan.
This likely means a T-19/1345 or 1356 combo because you have a linkage while the Zf-5 has an integrated hydraulic bellhousing and the bigger input shaft that won't work with your clutch.(the T-19 has a removable bellhousing with the standard Ford 'butterfly' bolt pattern)

Gary has information about 335 series flywheel swaps from Tim Meyer if you want to go down the 5-speed path, but you'd have to change the pedal box and add a master cylinder.

As Shaun said you need the front frame horns because they're pocketed for the spring shackles, unless you opt for Sky's frame box + RSK

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

ArdWrknTrk wrote

Gary has information about 335 series flywheel swaps from Tim Meyer if you want to go down the 5-speed path, but you'd have to change the pedal box and add a master cylinder.

Right. The bell housing bolt pattern for the M-block and 460's is the same, but the flywheel is about 3/8" farther back on the 460 than the M-block. So the ZF5's input shaft is too short to properly engage in the pilot bearing in the crankshaft on an M-block.

I designed an adapter that bolts to the crankshaft and moves the flywheel and pilot bearing back the needed amount, and Tim is making and selling them.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

Link

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

ArdWrknTrk wrote

Link

Gary, AKA "Gary fellow": Profile

WrenchingtheWretched

Re: Cab and chassis f350 2wd to 4wd conversion

In reply to this post by ArdWrknTrk

The plan would be to keep my 4 speed and do a divorced transfer case or find one that will bolt to the np435. I decided my vin a few weeks ago I forgot my axle ratio but I’ll go back through and get that info again.

“Big Yella”
1982 F350 Dually
400ci 6.6l
NP435 4 speed trans
Sawmill lumber flatbed

ArdWrknTrk

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

You'd need to find a new transmission output shaft and the 4x4 tail housing to 'adapt' a married transfer case to your existing 2wd NP435.
Then you'd need to completely disassemble and re-shim the gearbox to install it.

I'm not sure where you bolt the linkage or a divorced transfer case but I imagine you'll have to modify your own transmission crossmember and both drive shafts in that case.

Seems like a cool project.
Do you have a decent driveline shop in your area?

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

WrenchingtheWretched

Re: Cab and chassis f350 2wd to 4wd conversion

There are a few! Lucky for me I live just a short drive from Charlotte,NC. Tons of race shops etc. and even a few local to me. Realistically I want this 1 ton to be 4x4 but with all the labor, parts and things I’ll have to do since it’s a cab and chassis I think I’ll just try and find me a 150 4x4 manual with a 300 inline I feel like monetarily I would have the same in it as building what I currently have. I may still do the swap but. I’m a little discouraged now with all the roadblocks

“Big Yella”
1982 F350 Dually
400ci 6.6l
NP435 4 speed trans
Sawmill lumber flatbed

ArdWrknTrk

Re: Cab and chassis f350 2wd to 4wd conversion

Administrator

C&C doesn't make the difference.
It's that you have a 2wd frame.
In a 250 and above the 4wd models need front leaf springs.
There are no radius arms to locate the front axle.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

salans7

Re: Cab and chassis f350 2wd to 4wd conversion

I can attest, you're making the right decision. I don't know if I would want to go through everything I've done to make my truck what it is, ever again. But I also said that about my old F150, and then I went and 4x4 swapped my F350 too. At least the F150 was all bolt-in.