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1999 F250 7.3L 2wd to 4wd

28K views 13 replies 6 participants last post by  Uncle_T 
#1 ·
Hi, first post so i hope i dont mess this up

I recently just bought a 99 7.3 supercab shortbox for a great price
I had been looking for a 4wd but had no such luck finding one with such low km's

back on point, ive been doing my homework into converting it over and I just have a few more bugs i need to work out
I'm currently a 2nd year apprentice so I feel im capable of doing the work

I just want to make sure everything is a go before i begin

I have a twin I beam front end, As far as i've looked into I'll be looking for

A Complete solid front axe, (3.73) with a pair of leafs, a transfer case(electric shift) mainly because for some reason i already have the dash switch
New front and rear drive shafts

I've been trying to trace down wiring diagrams to see about the plug to the t-case aswell as my dash,

I had someone swear that its not possible, but after a few conversations with the local ford service mechanics, They said no such thing

I'm just looking to make sure I'm in the right direction, if this is possible and what else i might be in store for

Thanks
 
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#2 ·
You'll have to change the output shaft and rear cone on the tranny to install the t-case adapter and t-case. I believe the auto tranny has to either come apart completely or you'll have to swap the complete tranny to the 4x4 version. I think the rear of the manual tranny can be changed without a complete disassembly.

As far as wiring, you may find some of the connectors already on your harness, possibly plugged back into a dummy connector on the harness. But I doubt you'll find the connector for the electric t-case motor already there. My 4x4 is a manual shift and doesn't have the relay box for the ESOF relays under the hood or the wiring to them. I'd recommend you go for a manual shift t-case rather than try and install all the wiring for the electric shift. The GEM in your truck may need to be changed as well to control the t-case relays.

As far as the switch on the dash, it'd be easier just to abandon that, or get a new dash bezel w/o switch from a wrecking yard.
 
#3 ·
Alright, Some of the abbreviations are unknown to me,

I have a good friend that works in a transmission shop, and he assured me that with that tranny, all I'm looking to change is that one front cone, no disassembly needed

As for the wiring, i feel this will be the only trick part

I'd love to run the electric like i had said just cause of it being compact and ****, and not having to cut a whole in my floor

The manual Transfer case might be more realistic, I'm gonna put my truck up on the hoist tomorrow and do some more homework on if i have any plugs etc
 
#4 ·
If it was mine I would put the front-end from a 2005-up truck under it as those are coil sprung, as your truck is. You only have to change out the spring towers (grind/cut off rivet heads, replace with bolts) and then it is a bolt-up operation. This setup will also give you a shorter turning radius.
 
#5 ·
I have a good friend that works in a transmission shop, and he assured me that with that tranny, all I'm looking to change is that one front cone, no disassembly needed
What tranny are we talking about here? This info you are given may be what you want to hear, but it is not correct. Either the 4R100 or the ZF6 or the ZF5, you must change the output shaft, which requires disassembly of the trans. I don't know what part you are referring to as the "front cone".
 
#6 ·
Hey - I'm glad you pointed that out for me, I had him actually check into it and as you had said, some work is needed. I hope i didnt sound like too much of a punk, I was just going on what I was told. He can still do the work, mainly just the tailshaft is different? After I read your post i started to figure that it would be different size from the end housing too the extension housing for a t-case

I'm looking around for the parts i need strangely the hardest part i'm having to find is the axle with 3.73's

I havent made any final decisions yet on whats goin under it

I just figure I got a steal on the truck for a price with low km, After I'm done wit the conversion I'm sure it will be worth what i put into it.

So to add on now

I'm looking at, Mounting a Front axle(remove I-beam front end), I'm going to have to look into the steering I'm wondering what needs to be changed. I'm going to look into the wiring on friday for a electric t-case, although i have a feeling i will use a manual one. I'm curious what wiring im lookin into for a manual one?

I'll have to pull the tranny out, to get it worked on, which is alright because then i can just mount the t-case on it before i put it back on I was thinking
 
#9 ·
OK with the 4R100 you will need to have the trans completely torn down because the last thing to come out of the case is the output shaft. It will have to be replaced with a 4x4 unit. You will also need the adaptor that bolts on the back of the trans case so the xfer case will attach. Whether you get your trans rebuilt or freshened up at this time is up to you. Many folks just try to find a good used 4x4 trans, there is also that route.
 
#11 ·
Jstrauss... can you confirm, does the output shaft of the ZF6 need to be changed in order to go from 2wd T-case to 4wd T-case from a truck of the same generation? thx

I have a 2000 F-250 and considering this swap. My local wrecking yard has the leafs, front axle, t-case, and drive shafts from same year truck. It appears as though my frame is already drilled for the leaf springs from the factory. Seems like a reasonable project to do, but I want to make sure I wont run into issues mating the ZF6 to the t-case.
 
#12 ·
No.
1. There's no 2wd tcase.
2. You have to swap the whole transmission for a 4x4 model.


Sent from my SAMSUNG-SM-G935A using Tapatalk
 
#13 · (Edited)
Like 79Jasper said, you'll either need a 4WD ZF-6, or an output shaft and rear case section for a 4x4 style tranny AND a bearing rebuild set, and enough money to have someone rebuild it to swap in the output shaft. I don't know if you've priced a 4x4 output shaft lately, but plan on North of $500 just for that part. Simplest way is to swap your 2WD ZF6 for a 4WD one. The 2WD tranny has a driveshaft yoke on it, but on the 4WD version the t-case bolts directly to the rear of the tranny. your 4x4 donor truck will have to have the same wheelbase and transmission as yours for the driveshafts to fit, AND the T-case will need to be from a manual tranny truck, NOT an auto tranny truck. The input splines on the t-cases are different.

Easier yet would be to sell your 2WD truck and buy one in 4WD. But if you want a project........
 
#14 ·
Thanks guys for the detailed information.

I had not yet priced the 4x4 output shaft as I was unsure if it was needed. $500 is shocking for that part. The whole idea of this swap becomes way less enticing now knowing the tranny will need to be stripped down to install the output shaft. I'll pass for now....
 
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