I have been wanting to put a zf6 in my f450 for a while, but I am having one hell of a time finding a donor truck. The only truck I found with a zf6 for sale that wasn't gold plated is 2 wheel drive. I looked and an extension housing is about $350-400 so I can make it 4x4. I am not sure if a new tail is all it would need to put a transfer case on it, I can't find much on the topic. I remember seeing one or two super duty 7.3s that had a 5 speed. If I find an OBS with a 5 speed would I be able to use the parts from that? Since it's an auto, of course I would need all of the parts. If I would have to get a few things I am not worried, but I don't want to have to buy everything individually. Does anybody have and experience or knowledge on the super duties with a 5 speed? It is an F450 with 4.88 so the low gear you gain from the 6 speed I am not worried about, and the final hearing from what I understand is about the same so I am not concerned with gear ratios.

 

I've considered this same swap more than a couple of times. If you did pull the trigger on the swap, your best bet is a '95-97 donor vehicle. You might still have to get a Superduty computer for a manual trans though, not sure. With the donor you can salvage the Trans, Flywheel, pedals/master cyl, bell housing dowel pins, drive shaft and maybe the computer. Everyone says the ZF-6 is alot tougher trans than the ZF-5, but alot of people that casually pull, prefer the 5 gears instead of 6. Heavy haulers prefer the 6 with the granny low and higher OD.

Alot of people say you can build the 4R100 auto just as tough as the manual counterpart, but at the end of the day, its still a 4 speed and that doesn't thrill me. Also there are some ratio differences between the S42 and S47 versions of the ZF-5.


ZF-5
1st = 5.72
2nd = 2.94
3rd = 1.61
4th = 1.00
5th = 0.76


ZF-6
Low = 5.79
1st = 3.31
2nd = 2.10
3rd = 1.31
4th = 1.00
5th = 0.72

 

I'm not an expert... But I don't see a few hundredths making much of a difference. It also seems like 1st in the 4r100 is around 2nd in the zf5, and between 1st and 2nd in the zf6, so either way it will be gaining quite a bit in the low gear end of the tranny.

 

Yes, your correct. It was like 150 rpm difference between them at 65 mph.

 

What's your budget? I bought a brand spankin' new ZF6 a few years ago from Joe's Transmissions in Pit, PA. It was out of Canada.

 

Probably not that much haha!

 

I bought a new trans from them lasy year as well. Worked great other than a messed up clutch.

I have had a ZF5-S42 a ZF5-S47 and three ZF6 transmissions and pulled with all of them. The one thing that I do not like about the 6 is 2-3 step is a 0.79 ratio change and loaded heavy it is rung out in 2, and upshifting to 3rd there is a big drop in rpms. It needs a gear between 2 and 3 at least pulling 7-8% grades here stock and 3.73 rear.

 

Thanks for the info on the gears in the 6 speed! That's a good thing to know going into a project like this! I do pull trailers regurarly of up to 10000 pounds or so, but being an f450 with 4.88 rears its not much work for it.

Does anybody know if any of the gassers have the same bellhousing bolt pattern? There are quite a few 460s and other big blocks that are 5 speed around here, way cheaper and easier to find than a 7.3 with the right tranny. So, if it's the same pattern and they are built the same I will go with that route.

 

Not the same pattern gas to diesel.

 

Anyone have more information on the new ZF6?

 

They are new old stock from a warehouse/dealer. They supposedly keep them currently in a warehouse out of the elements.

 

The name of the place was Joe's Transmissions in or near Pittsburgh, PA.

Here's my ordeal. I went big and made my own cooling system for it, which I'm happy with.

https://www.ford-trucks.com/forums/1...ot-good-4.html

 

Thank you. I'm looking them up now.