Q I have a '79 Jeep CJ-7 and cannot decide what rear axle to put into it.
I'm 29. I bought my Jeep when I was 16 and have been modifying it ever since. It was my daily driver for many years; however, I still drive it as much as I can. My old Renegade is far from stock now. It has a Cummins 4BT engine, an NV4500 transmission, a Dana 300 transfer case with a TeraLow 4:1 kit, a Grand Wagoneer front Dana 44 that has been narrowed to widetrack CJ width, an ARB Air Locker, 4.10 gears, and crossover steering.
My dilemma is the rear axle. I have an AMC 20 with 4.10 gears, a Powertrax locker, custom six-lug Moser one-piece axleshafts, and Grand Wagoneer backing plates and drum brakes. The axle is, you could say, U-shaped, not straight. The axle seals leak a bit, the diff-cover is smashed up, I recently broke a shock mount, and to make matters worse, last month my left rear wheel was not tightened securely and my brake drum came crashing to the ground and damaged my brakes. The brakes work, but will not pass inspection. I have previously vowed not to put any more big money into the rear axle (yes, "big money" includes the cost of new brake drums and pads.) I built up this axle 10 years ago (same time I built the front 44). Soon after, I decided that I would just put a Dynatrac Dana 60 in my Jeep when the AMC fails me.
The CJ is turning 37-inch rubber, and I want to start wheeling longer distances. I live in Pennsylvania and would like to get out to Moab in the next year or two. So, I'm now married five years and have a 20-month-old son and another child on the way. What rear axle would you recommend for this particular setup? My desire is a Dynatrac ProRock60, but I would have to be very intentional about saving up for it, and even that would take longer than my Jeep can wait for a new rear axle. I've considered having an axle from a fullsize truck cut down to fit my CJ, but I really like the high-pinion idea (since my Jeep is sprung-over).
There seem to be limited resources out there for my particular need. What have others done? What would you recommend? What could I do for, say, half the price of a ProRock and still be happy?
A I'm of the frame of mind that you get what you pay for, and I definitely feel that way about Dynatrac's axles. The company's sales guys, engineers, welders, and gear techs all strive to build the best parts possible. For example, I saw one of the Dynatrac welders take the time to start and finish the weld on the bottom of the axletube, out of view, making the housing look that much better, and this on a strong double-pass weld that holds the knuckles on the tube. It's that type of pride in one's work that makes you feel good buying Dynatrac products, products that are mostly made in America. Now, I'm not saying these axles are cheap.
Many Jeep guys stuff GM 14-bolt axles and Dana 60s from 1-ton '80s era pickups in their Jeeps with great results. These low-pinion axles do have driveline issues, but with the many wheelbase stretching options available this can be gotten around.
There really isn't an easy high-pinion rear axle option for your Jeep. Other than a custom-built Dana 60, the only other reasonable rear would be custom 9-inch housing like a Spidertrax or Currie with one of the true Hi-9 dropout carriers. These are very strong and could be built to your specifications.
I think the biggest catch is your wanting to narrow the housings. This will require special axleshafts, retubing the housing if done properly, and a complete rebuild of the axle inside and out. Before you go this route, I'd get a price from Dynatrac. I think you might find it in the same ballpark, and you would be getting completely new parts.