Part 4: Swapping a Ford 8.8 rear axle
Last month, we presented T&T Customs' very nice long-arm suspension system, and we then headed off to Moab where we gave it a "trial by trail" evaluation.
It passed-in fact, it did better than we anticipated. The front axle needed to be shifted a bit to the left to center it, and more caster angle added to improve pavement tracking, but otherwise we were pretty dead on. Low-speed wheel articulation was outstanding, even with our Addco sway bars hooked up. However, after three days of trails, the stiffener bar overloaded our connecting links, and they bent into snakelike shapes to the point where they had to be disconnected for the remainder of our week. (Yes, we have since replaced them with some new stronger tubular ones.) Dry sandy washes and dirt roads were a flat-out blast to run at speed as there was just the proper amount of tail-end oversteer to let us power through a controlled drift.
We're still working on some pavement tracking and roll steer issues that hopefully we will soon solve. We will be sure to give you a year-end update on our final conclusions.
Something to keep in mind is that the long-arm kit from T&T Customs is at the top end of suspension systems in quality, ride quality, usability and, unfortunately, price. This is not the suspension for the guy who just wants to raise his vehicle to obtain the "cool off-road-ready" look. It's designed for the hard-core user who wants the very best. The detail and precision of all the bracketry is, in a single word, outstanding. Professional welding skills are definitely needed to do the installation.
Now, let's jump back a few months to the drivetrain modifications and start with the rear axle. We weren't quite sure what we wanted to do in the rear. Yes, the Grand came equipped with a Dana 44. But here was the problem: it's a hybrid 44 with an aluminum centersection, weak axletubes, C-clip drive axles, and no aftermarket support. Only two gear ratios are offered: 3.54:1 and 3.73:1. Ours had the 3.73:1s because of the trailer towing package, which would be marginal with our planned 33-inch-tall tires.
We did have a Scout Dana 44 stashed away that we at first considered using, but it had drum brakes and a 5-on-51/2 bolt pattern. Yes, we could have converted it to a 5-on-41/2 bolt pattern and even added disc brakes, and perhaps that is what we should have done, as in the end the overall price would have been less.
Instead we went with a '95-and-later Ford Explorer 8.8-inch rearend. We got the disc brakes, the same ones used in a lot of aftermarket conversion kits, a slightly larger ring gear (8.8 versus 8.5 inches), and 31-spline axles (that still had C-clips for retention).
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The drawback with this axle is that it was about 1.25 inches narrower than the ZJ's original. To bring the track width back out, we located some billet-aluminum spacers in Jegs' catalog that centered on the axle hub, not on the lug studs. That also meant longer studs for proper nut engagement, and Moroso had the ones we needed. Then we had to drill out the stud holes in our stock axleshaft flanges a bit for a proper pressed fit. Actually, just after we did this, Alloy USA shipped us some very nice replacement axleshafts made from double heat-treated 4340 chromoly material that carry a 10-year warranty against breakage. While still a C-clip design, with our present tire and motor combination, we are confident that we will never break them.
The axle flanges were drilled and tapped for either the 5-on-51/2 or the 5-on-41/2 bolt pattern. The supplied screw-in studs weren't long enough to use with the spacers, so some Moroso stud/bolts were used. However, upon installation, we found the heads hit the emergency brake, and we ended up hand-grinding the head a considerable amount for proper clearance and using a red stud locker to make sure they would not back out.