258 Carter BBD Idle Problem
AMC 20 Axle
AMC 242 4.0l Engine
AMC 258 I6 Engine
AMC 304 V8 Engine
AX 15 Transmission
AX 5 Transmission
Dana 30 Axle
Dana 44 Axle
Front Dana 44 Axle Swap
Jeep CJ Gauge
Jeep Engine Upgrades
Rear Dana 44 Axle Swap
Swapping Early Bronco Axles into a YJ
Who in their right mind would take a perfectly functional 9-year-old
Jeep YJ, rip out the entire undercarriage, and replace it with
parts from a 25-year old Ford? Chances are if you're reading this
then you understand already, but for those of you who don't...
Stock YJ axles are a relatively weak link in an otherwise excellent
vehicle. If you want to run tires over 31", especially with lockers,
then the odds of breaking an axle shaft or u-joint, or even bending
a housing, go way up under even moderate usage.
The early Broncos, on the other hand, were big, heavy, and thus very
solidly built. The stock axles for a 1973 EB were a standard-cut Dana 44
up front and the much-praised Ford 9" in the back. In a YJ they make
for a very stout combination and reduce the odds of breakage even with
large tires and lockers.
The brakes are bigger all around (I've
ended up with 11" discs and 11" drums). The axles are about four
inches wider than on the YJ, which is nice for a little extra stability
It was a cool project. Early on in the game I discovered that I couldn't
find anyone who had ever done this swap before, so from then on it
became a personal challenge. Something about the risk involved appealed
to the fool within me. That and I had no idea what I was really getting
into. My most ambitious project before this was an on-board air system
(not even in the same ballpark) and while I'm mechanically inclined this
was way beyond anything I'd ever done before.
How did it start?
Before the swap, My Jeep was a relatively stock 1989 YJ. It had 2.5"
OME lift springs in it and 31" AT tires, and that was as far as I
thought I wanted to go with lift. Then Larry Soo (aka lars) got
involved. I remember one conversation:
Larry : "You should do a springover. Hmm... springover with OME
Me: "Uh, yeah, right. Heh heh."
But the seed was planted. I'd wanted to get a rear locker for
a while, but didn't like the idea of throwing $$ at the stock D30 and
D35 axles after hearing them bashed so often on the Jeep-L and
Some time later, Larry told me about a friend of a
friend who was selling a pair of axles from an old Bronco. I went over
to see them. They looked terrible! Covered in rust and some kind of
green mildew, but the potential was there! The rear end had the stock
28-spline axles, and the front had a standard-cut diff and drum brakes,
but the width looked good and they had 4.10 gears in them.
Next thing I know, I've purchased the axles and I'm planning a
spring over axle conversion.
Preparation and installation of the Ford 9" rear from an Early
Bronco into a Wrangler YJ. The Ford 9" is massive compared to
the stock Dana 35c.
The early Bronco Dana 44 had 30 spline shafts, 8.5" ring
gear, and real hubs. There are many advantages of a Dana 44 front
end in a Wrangler or CJ.
Doing a spring over conversion on a Wrangler YJ for maximum
articulation. The conversion is a bit more work than a normal
lift, but the results are amazing.
Some final notes on the spring over axle swap and early Bronco axle
swap. Important things like wheel bolt patterns must be considered.
Last modified Wednesday, 01-Dec-2010 09:23:45 MST
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