Greetings everyone!

Trying to find some information on swapping in a zf 5-speed in my '78 f250 4wd. I will be swapping in a 460 as well. I am 99% sure the np205 will bolt to the transmission with a little trimming. I was wondering if anyone has done this swap and if they ran into any major snags along the way. Thanks for any info.

 

This is a very straight fowards swap if you find a trans for a 460 engine and not a diesel. While the diesel will work, it takes a little too much work to make it a very worthwhile swap. I used a diesel trans and found myself in a pickle. I did not know it was a diesel, and assumed that it was a 460 pattern. They are close when the adapter is not installed.
Anyway, you will have to grind a small portion of the trans / t-case adapter to allow some clearance for the range rail, and shift linkage.


Obviously you will have to add a master culinder for the hydraulic actuated clutch, change the crossmember/ make one or modify yours and make d-shaft corrections. Other than this it is a breeze.




Here you can see where I had to re-drill the holes to match a 460 pattern. The top bolts were fine, but the others just missed. Notice the newly machined holes and the lack of starter bolt holes. This quickly became interesting. See the cast iron adapter has the provisions for the starter when used with a diesel, and trying to convert one is not easy.
I made it work, but it would have been easier to find the correct trans.

 

Excellent news! I had a pretty good idea it would work. Thanks for the pictures and detailed notes. The transmission I have was bolted to a 460 so I should be in good shape. I knew the transmission cross member would have to be moved and the drive shafts lenghtened/shortened. I have a set of '93 clutch and brake pedals that I might be able to graft in for the hydraulic clutch. Now that I have confirmation on the transmission I can jump in with both feet and see if I can swim. Thanks again, I know it took some time with the pictures and the descriptions. I appreciate your time.

PJB

 

its no problem. Its always fun to share and even show off a little. Not many have taken this approach in a 4wd, and knowing that others are out there taking the plunge adds to the wow factor.
For the record, I used stock 78/9 pedals, and just added the linkage and master for the clutch. Pretty easy, and I did not have to change anything, so it still appears very stock.
I am sure that the later pedals are almost identical, but they are a pain to get out.
ONly real problem is the clearance on the brake booster. If you have a giant one, you might have trouble here. Other than that, it is a cool swap.

 

How did this project work out for you? I have a C-6 and need to cut down on the RPM's. what linkage did you use? I was thinking about using an aftermarket (kit car type) clutch set up. I also have an NP205 i have to think about.

 

Linkage? Linkage for what? The transfer case linkage is on the case in the pics and it is all stock This came off an old 4 speed and bolted right up to the ZF. Small modifications are all that are necessary. It now sports twin sticks, and individual sift linkages.
As for the clutch stuff, this is all late model hydraulic clutch stuff. Remove the donor master cylinder for the slave, and mount it to the firewall. Make a linkage for this, and bam. you have a clutch.
Keep in mind that this is not a cheap swap, so if all you are wanting is lower engine rpm, why not consider a gear ratio change?
The 5 speed is probably better suited for a veriety of ratios rather than just its overdrive capability. I mean really the final drive is only a .76, so if you can deal with a slightly different rear end gear, you may be dollars and cents ahead.

 

i appreciate the gear change idea. I will be going in with lockers for both axles. Besides shifting is not high on my knee's priorities. (due for another surgery)

 

couldnt you just use the stock mechanical linkage? and not go hydraulic?

 

My ZF is hydraulically actuated. No provisions for mechanical.

 

yes there is. there is the clutch fort sticking out the side of the bellwhere the external slave pushes on it. Just have your stock rod push on that. I could see if it had an internal slave cyl

 

I would imagine that the bellcrank would have to be modified to accomodate the slight differences in throw. I could be completely wrong but I would not run a mechanical linkage anyway.
Header clearance is limited regardless, and once the frame starts to twist up some, the hydraulic clutch has far more advantages. easy to just throw in a master. So much easier to push too.

 

my zf has the internal slave and they only hole in the bellhousing is where the line goes in.

 

You my fried dont have a ZF then

 

yeah i do.. 91 F-150 4wd ,300 inline 6 and a zf Bought it as a parts truck to swap the tranny into my 79. May be more holes but none to mate up to a mechanical clutch

 

He might have a ZF. What he doesn't have is a 460. The small block zf's (came behind 300s and 351ws) do have a concentric slave (very crappy system) that can't be replaced by mechanical linkage. The 460 zf does have an external slave that actuates a rather standard looking clutch fork. In my ZF swap into my 79, I did use the mechanical linkage as I'm not a fan of Ford juice clutches. Another consideration to the hydraulic vs. mechanical question is firewall stiffness. I am of the opinion that the firewall in our trucks isn't stiff enough for a hydraulic master and will eventually crack.