I thought I was done with Project Hellraiser 4 but after a
roll in Mammoth the
other weekend I find the buggy is in need of a new rear end.
After first glance it didn't look too bad. The spindles that were butt
welded to the Dana 60 center section both broke at the welds (and it was the
welds, not the material in the HAZ zone). Initially I thought with a
little quality time on an axle jig I could resurrect the old axle assembly.
But as time wore on it was becoming clear it would be cheaper to just start from
scratch. The above picture is the short side axle which we had to pound
back out thru the spindle to make trail repairs. As you can imagine this
had some repercussions with the spindle, namely it went from being round to
something closer to an egg shape.
On later inspection I found the long side axle was also tweaked along with some
nasty bends in the
axle tubes themselves. It wasn't looking good.
I then held out hope that the center section was ok and useable but upon opening
the diff cover I discovered that was not the case. The pinion gear had
shredded itself. Before I even got to this point I was 90% sure I was just
going to install a new rear end but these findings just confirmed my line of
reasoning was correct. The only good parts remaining, the spool and 1410
pinion yoke would become spares for the front axle.
Since I am still paying off the 4 seater buildup I had a pretty tight budget
which would become the driving force in my choice of replacement axle. However, to be fair I
made a spreadsheet and compared a few options: building a Spider 9, building
another 35 spline D60, building a D70u and building a 14 bolt. I gave up on the
Spider 9 idea after reaching over 4k in parts, it was just too much money for a
little extra bit of ground clearance and a potentially weaker gear set. The D60
and D70 fell by the wayside when I found the perfect 14 bolt axle which happened
to be sitting in Jack's back yard.
One of our former members started to build another rig but then canceled the
project. He had already installed a mini spool into the 14 bolt, installed a new
beefy differential cover, some new bearings and seals in the hubs along with
some fresh rotors and wheel studs.
I also got the weld on disc brake brackets and a pair of spare axle shafts.....
.... and a set of single rear wheel (SRW) hubs. Total cost was $400.
For reference, that's about the cost of a bare Spider 9 axle housing (with no
Here's a comparison shot of the dual rear wheel hubs (DRW) vs. the SRW hubs, the
SRW hubs will narrow the axle by 4 inches overall which puts me within .75" of
the front axle width. I just had to swap the new bearings from the DRW
hubs to the SRW hubs.
Since this axle still had stock gears (4.10's) I ordered a 5.13 gear set to
match the front axle,
an install kit and new ring gear bolts from Randy's Ring and Pinion at a cost of
nearly $300. This puts my total for a new rear axle (with spare shafts) at
Now the downside: this axle is commonly referred to as "the rock plow".
While the 14 bolt ring and pinion is a big upgrade over the D60 setup, that same
plus becomes a negative when you factor in the center section which houses it. I
measured the ground clearance to be just over 2 inches less than my shaved 60
housing. I am hoping between the sticky tires I run and some better driving I
can overcome the clearance deficit. I suspect the hardest thing to overcome will
be getting used to a centered rear differential since my previous setup was
offset to the passenger side.
It is possible to cut 2" off the bottom of the 14 bolt housing, plate it
for a net gain of
1.75" of ground clearance. The only problem with this plan is it requires
you to shave the ring gear down as well which I just don't have time for.
so I am going to try a different approach, I want to see if I smooth out the
bottom of the 14 bolt housing eliminating any hang up points if I will notice
much of a difference from my old shaved 60 housing with more ground clearance.
The picture above shows the bottom of the 14 bolt housing and the large rock
catching lip it has in stock form.
I used a sawsall to cut the lip into smaller sections.
Then I cut the small pieces off one by one.
I then switched over to a grinder and started smoothing all the edges out.
the dark indent in the lower left hand corner of the first picture still looks
like an edge but it is actually a smooth transition.
Here's a before/after comparison. After roughly 2 hours of work I had an
extra .50" of ground clearance and a smooth bottom ;) If you don't want to
keep the lower two bolt holes you can actually gain another 1" of clearance by
wiping them out but you'd have to modify the diff cover and plate the bottom of
the diff. I really wanted to keep all the diff cover bolts this time so I
ground the housing down to within .375 of the lowest bolt hole. I may actually go back
and take a little more off with the grinder right at the peak after seeing how
much meat was still left when I installed the new gear set.
I went with another Ballistic Fabrication rear axle truss this time around.
The original on my D60 was a little too long for use on the 14 bolt axle (the
D60 was offset so I had that truss made about 8" longer than the default).
The one problem I realized after installing the truss was I no longer had a good
target for the rear air bumps so for now they are removed. I am not sure
if I am going to add them back into the mix as I wasn't utilizing them in the
previous setup (there were no signs of me ever bottoming them out).
Even though this is a stock 14 bolt with a centered differential, the actual
differential housing is not really centered. The pinion itself is the
centerline so the truss is actually offset to the driver side a bit which makes
the swaybar look like it is offset to the passenger side.
For future reference here are what the link angles look like from the side view.
I also thru a tape measure under the differential and discovered I had only lost
an inch of ground clearance VS. the shaved D60 I had in there previously, I had
11" under the lowest point on the differential with the tires at trail pressure.
After 4 days of trail riding I couldn't tell I had lost the clearance and the
rig performed as if it never had extensive surgery, not bad for a grand total of
$700 into the rear axle and another $140 or so for the tabs and truss.