2wd to 4wd conversion

[Edward Michael]

Considering on this upgrade to the 85 F350 Crewcab 460 4spd.

Keeping 4spd or upgrade to zf5.

Application is tow/hauling truck on mountain roads & slow lane highway in sun, rain, mud & snow.

The donor truck is an 85 F350 long bed, single cab, 460 automatic.

Any input? Thanks.

[ArdWrknTrk]

What year is the donor?

Does your truck have front leaf springs?

Do you want to go to an automatic, or are you going to find a 4x4 manual gearbox?

If swapping the automatic do you have the whole truck, or will you need to find a steering column, kick down linkage, pedal assembly, cooler lines, etc...?

[Gary Lewis]

I'm not sure why, but I got myself confused. So, let me restate what I think the question is:

You have a 2wd '85 F350 Crewcab w/a 460 and a 4-speed, and want to convert it to a 4wd and maybe a ZF5, but if not retain the 4-speed. And you have a 4wd 85 F350 long bed, single cab, 460 automatic as the donor.

If I have that right, and reading between the lines on what Jim asked, I believe that both trucks have leaf springs as they are F350's. In that case, the front axles should swap But, I think the issues are:

• Transmission: You will have to have a different transmission as the transfer case bolts to the back of the transmission and there's no place for it to do so on a 2wd transmission. So, why not go to a ZF5 at the same time? It will also take a different clutch due to the larger spline on the ZF, and you will need to replace the throwout bearing, clutch plate, and release arm as well.

• Transmission Cover: You will need the taller transmission cover from a truck with either a ZF5 or E4OD as the cover you have now won't clear the tall ZF.

• Axles: You need to check the axle ratios on your two trucks. If they are the same then you are fine,

  but if different you will need to swap rear axles as well since the front and rear axles must match. You can find the axle codes here: http://www.garysgaragemahal.com/axle-ratios.html

• Rear Transmission Support: The ZF is about 1" longer than your T-19, so you will either need the proper crossmember for a ZF, which accomodates the extra length and bolts into the original holes, or you will have to drill new holes. However, that isn't easy on the top holes as there is little room to get between the frame rails in order to drill straight up, and the cab is so close you can't get bolts in there.

  If your rear cab bolts aren't rusted too badly you can pull them and raise the rear of the cab a bit to get enough room to work, but it isn't easy and the proper crossmember would be better.

• Backup Light Switch: The ZF has a different connector than the T-19 for the backup light switch,

  so when you get the ZF be sure to get the wire harness for it as well. (And the clutch, pressure plate,

  throwout bearing, and release arm if you can.)

You should be able to use the transfer case and its shift linkage from the donor truck, as well as the front axle and driveshaft.

[85lebaront2]

Unfortunately, you are going to run into what I looked at. Your truck, like mine has twin I-beams with king pins and rides on big coil springs and due to the layout, if you put the twin traction beams you would need to attach the leaf springs and hangers. To use a live axle, same if you use a leaf spring style like the later (up through 1997) trucks used. The best design would be like the Dodges use, coil springs, track bar and radius arms, problem being, Dodge and GM run the 4WD front shaft down the right rather than left side and since you would no longer be on a pivoted axle half, the spring rate would need to be lower.

You might do some research into what is offered aftermarket for suspension options, me, if I did it would be to try to keep the coil springs.

[Gary Lewis]

Unfortunately, you are going to run into what I looked at. Your truck, like mine has twin I-beams with king pins and rides on big coil springs and due to the layout, if you put the twin traction beams you would need to attach the leaf springs and hangers. To use a live axle, same if you use a leaf spring style like the later (up through 1997) trucks used. The best design would be like the Dodges use, coil springs, track bar and radius arms, problem being, Dodge and GM run the 4WD front shaft down the right rather than left side and since you would no longer be on a pivoted axle half, the spring rate would need to be lower.

You might do some research into what is offered aftermarket for suspension options, me, if I did it would be to try to keep the coil springs.

Ok, so that's what Jim was getting at? My apologies. I didn't realize that it would have coil springs.

I assumed since the F250HD has leaf springs that an F350 would as well.

[NotEnoughTrucks]

What year is the donor?

Does your truck have front leaf springs?

Do you want to go to an automatic, or are you going to find a 4x4 manual gearbox?

If swapping the automatic do you have the whole truck, or will you need to find a steering column, kick down linkage, pedal assembly, cooler lines, etc...?

One option to the front axle dilemma would be to use the coil sprung solid axle from a late model SD truck. I have a scrapped 2006 F250 SD and that is exactly what I have been contemplating. Those leaf springs sure don't ride nice! The only downside is the bolt pattern strays from the 8X6.5 we know and love. Probably best to swap the rear diff as well.

[ArdWrknTrk]

Ok, so that's what Jim was getting at? My apologies. I didn't realize that it would have coil springs.

I assumed since the F250HD has leaf springs that an F350 would as well.

Gary, as you can see the first post has been edited, so there is more for me to work with.

But (of course) I forgot to check the notify me box.

So....

[Gary Lewis]

Gary, as you can see the first post has been edited, so there is more for me to work with.

But (of course) I forgot to check the notify me box.

So....

Jim - Now I see why I was confused as to why you were confused. I missed that the original post was edited after you posted. Duh!

[ArdWrknTrk]

Jim - Now I see why I was confused as to why you were confused. I missed that the original post was edited after you posted. Duh!

It's a lot of work to swap from coils to leafs.

Alignment is critical.

And you need a a 4x4 gearbox plus the driveshafts.

I do not know/think the C6 + adapter and transfer case is anything close to the length of a T-19 + adapter & TC.

If it is as long as I suspect then you are going to be dropping a few bills at the driveline shop.

Personally I would never go to the later metric lug pattern.

Though I've considered getting a E-series van rear for the disc brakes.

They kept the old lug pattern, but had different frame width, so perches need to be moved.

[Ford F834]

I will refrain from commenting on the technical aspect of a leaf spring TTB swap since I have not actually done one, but... I recently did the *much* easier direct bolt in F150 4x4 conversion and my take-away lesson is that it is a really big job that I would probably not do again unless it was for a VERY special truck.

An older crew cab might very well be worth it, since 4x4 crew cabs are few and far between. However, if you are going to go through the effort of converting it, my strong recommendation would be to not mess around with a TTB. Source a Dana 60 straight axle and install it using a reverse shackle kit. They make them now that fit our frame horns and that is as close as you are going to get to a bolt in mount. It will be a better stronger truck with worlds less headache, but considerably more expensive because of the D60 axle prices. Locating a F350 straight axle ZF-5 donor would be ideal.

In the for-what-it's-worth department, diesel guys can swap a 4x4 ZF-5 into a T19 or a C6 truck with no modifications needed to either driveshaft. The 460 ZF is identical except for the gear ratios and slightly different bellhousing holes (if you look at a diesel ZF you can even see slight traces where the 460 holes would be). The 460 guys may correct me, but I suspect they can be ZF swapped without driveshaft modifications also.