You can replace the crossmember (the 4x4 crossmember is wider)
If you want more or less a stock-ish 4x4 "on the cheap"
I'd go junkyarding to your local U-pull-it junkyards find a
complete donor 4x4 FRAME.
Clean (sandblast) rust proof (phosphate) Paint the frame attach the
front axle to it and start swapping your stuff onto it.
Moving the bed can be done by two people.
Moving the cab usually takes four.
It can be done if you have the right junkyards and the time and
energy it is far from "impractical" to do it.
but I'll say this:
back about a decade ago one of the 4x4 magazines had a letters to
the editors column and on that page someone asked about converting
a 2wd to 4x4 and after a longwinded reply stating that it wasn't practical
to consider let alone actual do the editor went on to the next letter...
the rest of the story?
On the VERY NEXT PAGE....
Visible without turning any pages.....
Was an artical about cutting the IRS front suspension of of a late 80's Full size Chevy and doing an SAS conversion....
I have yet to hear any arguement from anyone that doesn't
make me want to kill them for gross stupidity for attempting
defend that article.
The ONLY thing that didn't need to be done to convert that FS Chevy
to a SAS that would have bene different from converting a 2wd the
same way was that the chevy already had a 4x4 trans and t-case
I've come to believe that converting an exsisting 4x4 to an SAS is a
waste of a perfectly good stock 4x4. and that nobody has any reason
to object on logical grounds to doing the same thing to a 2wd.
so if you REALLY want a 4x4, while trading to a 4x4 is "easiest"
Swapping your body and power train onto an exsisting 4x4 frame
will give you a major sense of accomplishment that you won't get
from buying one.
Actually converting a TIB truck to TTB is a hard dirty job
and it's practicality is more a matter of your machanical skills
and access to the right equipment.
But if you actually want a serious offroad truck with a solid axle up
front there are few supportable/logical reasons to start your
conversion with a 4x4 truck.
and in favor of converting a 2wd there are fewer leftover useful parts
you will need to feel bad about scrapping when the job is done.
Personally I converted my 1987 2wd supercab t 4x4 with 1997 TTB front parts.
But I didn't ask anyone opinion on if I should do it
Or HOW I should do it.
I knew EXACTLY what needed to be done and simply did it.
And while I was doing it less than 20feet away was a complete
1990 4x4 supercab frame assembly that I could have simply moved
my body onto...
why didn't I? I had already mad modifications and additions to my frame
that I didn't want to duplicate AT THAT TIME and doing it the way I did it
saved me several days of work
It took me an hour or so to both drop the 2wd front suspension
and remove the crossmember.
It actually took me longer to grind the original welds off AFTER the
crossmember was laying in my scrap bin in multiple pieces
Loosening my body mounts (that I needed to disconnect anyway
to replace them) actually took longer than it did to spread the frame and ut the replacement 4x4 crossmember in....
But all this MUST be tempered with one major fact... that I know
the gen1 and Gen2 rangers about as well as anyone else on earth
I don't often ask questions, It's my job to answer them...
After that long winded exercise in giving myself carpal tunnel syndrome?
Short answer? Replace the entire damned frame.
I'm actually going to the U-pull-it this weekend to harvest a 1992 Longbox
std cab frame to convert a friend's 1991 2wd longbox to a 4x4.
As a note if you ever desire to convert a TIB F-series from 2wd to 4x4 with aTTB front suspension? the ENTIRE job can be done with a socket set.
the suspension attachments are EXACTLY the same.
Years ago my brother and I converted a 1993 F-150 shortbox
(actually it was a 1993 Lightning) from 2wd to 4x4.
the entire job took six and a half hours...
and some of that was a quick trip by me to run to the junkyard
to grab a set of longer U-bolts so we could put the factory blocks
between the axle and the springs
IF you KNOW the truck well enough there is very little you need to ask...
AD