Convert ZF5 2WD to 4WD---Is it Possible?

[Sparks-IDI]

I just picked up two trucks...well one and a half really. Complete '94 dually is factory turbo VIN K unmolested automatic. The '92 parts truck has ATS turbo, manual 2WD. I'm wanting to make the dually 4x4 manual. I'm looking now for a late 90's super duty axle (Dana 60) which I intend to install using a reverse shackle setup like what Sky Off Road does.

Now, trying to find a ZF5 4x4 tranny that's not crazy expensive is a challenge. I have been checking bone yards, Craigslist and Marketplace and so far no luck. I got to wondering is it possible to convert a 2WD ZF5 to 4WD? With a swap of case back halves? I have 2WD sitting right here and was wondering if it was possible without going off the deep end? If reasonably possible, where would I find the parts? Thoughts?

 

[Nero]

I looked into this years ago before I finally found a 4x4 zf. You will need two main parts if you can find them, the main shaft is longer on a 4x, and the tail housing is different. The other option is to do a divorced t case.

 

[IDIBOBS]

Tail shaft and housing are both available to make 2wd to 4wd. However it may prove very expensive. 200-250 ish for the tail shaft and $800ish for the housing is pretty common. Like mentioned, you do have the length for a divorced t case.

 

[IDIBRONCO]

the main shaft is longer on a 4x,

IIRC, the back end of the main shaft is also different, not just the length. The 4X4 uses splines while the 4X2 has a threaded end.

 

[franklin2]

No one has mentioned yet, besides the cost of the parts, you have to tear the transmission completely apart to convert it.

Look a little bit more, and see if you can find a 2wd superduty. One of the early superduties before year 1999. While these were 2wd, they used a 4x4 transmission from the factory. They had rear disc brakes, and they used a parking brake mounted on the back of the transmission. To mount the parking brake guess what they used? A 4x4 style transmission. Pull the parking brake assembly off and you have yourself a 4x4 transmission. Search the junkyards and all your sources again and see if one of these early 2wd superduties may have been overlooked.

 

[IDIBRONCO]

Look a little bit more, and see if you can find a 2wd superduty.

That would be a FSuperduty. Ford changed the heavier pickup line to have the name Super Duty for the 1999 model year. The ones that you want have this fender emblem.

 

[Sparks-IDI]

Franklin2, Like this one? So a BW1356 transfer case will bolt up to this once brake is pulled off, splines match? If so, this one is just down the road from me here in Melbourne, FL.

 

[frankenwrench]

That would be the one! That's the same one I used to convert mine to 4wd. 1345, 1356, and 4407 transfer cases fit that pattern under that brake drum looking assymbly that i am aware of. May fit more types of t cases, but I am unsure as I have only used those 3 to bolt to mine.

 

[Sparks-IDI]

Also found this. ZF6. 6 speed. Ad says from a 2001 7.3 F-550 4x4. Any big advantage to go this route? Did not even know there was a 6 speed for these trucks. Wow... pretty cool only thing is you will be doing a lot of rowing, which is not a bad thing. I was wondering about the gearing and how it stacks up against a ZF5. Probably really good if you do a lot of towing, pulling heavy.

Guy says internals are good just has a cracked case. I have a machine/fab shop so I'm sure I could machine/fabricate/weld a patch for the missing piece. He's asking $700. Thoughts on which tranny to go with ZF5 vs ZF6?

 

[franklin2]

zf6 is not a bolt in. And also requires a different transfer case. The gears are the same as the zf5 on the extremes(1st and 5th), they just added another gear in the middle. Not necessarily a bad thing with our engines, but the modifications I don't think are worth it to make it fit.

 

[Sparks-IDI]

Franklin2, I just want to confirm something. Any transmission bolted to a 7.3 Powerstroke will also bolt to a IDI 7.3 and vice a versa, true? So if true, the Zf6 should bolt directly to the '94 IDI. What modifications are you referring to? I'm assuming trans mount, maybe transfer case bolt pattern, requiring a particular transfer case. Regarding transfer case my only requirement is I want a manually actuated, not an electrical one. Can you elaborate a bit more.

It's not like I'm definitely going this route, just wanting to understand what is externally different about the ZF5 and ZF6.

 

[asmith]

The Zf-6 is longer than the 5, it takes different transfercases, and I believe it needs a pump to a cooler for the fluid.

 

[IDIBRONCO]

and I believe it needs a pump to a cooler for the fluid.

Without knowing much about them, I think that the pump is internal. I can remember seeing transmission cooler lines that looked like they belonged to an automatic transmission. I don't remember seeing a separate pump.

 

[Rdnck84_03]

The zf6 requires a special made adapter plate, the zf 5 requires a 1 inch spacer to bolt to a 7.3 powerstroke, the zf6 doesn't require a spacer on the powerstroke. This means you need so shave 1/2" off the zf6 bellhousing and 1/2" off the engine adapter.

James

 

[Nero]

Ive been on and off googling this since the thread started. Definitely requires some fab work.

How to put a 6 speed ZF in a 2wd IDI

Ok, I am still getting occasional requests for info on how to do this swap, so I'll make a post with all the info I can remember on how to do it. It's been almost 2 years since I did it, so please excuse anything I forget to mention. I now have about 20,000 miles on the truck with the...

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