Send your Gearhead questions to:
- Off-Road Adventures, Gearhead Dept.
- 610 West Walnut Street
- Compton, CA 90220
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Axle Info
I have an ’78 F250 4x4 and need info on the front and rear axles. Front axle BOM 610040-2, rear axle BOM 603901-2.
Dean Holt — Via e-mail
Front is a reverse cut ring gear Dana 44 with 3.54 gears and an open differential. The rear is a full-float Dana 60 with 3.54 gears, an open differential and 30-spline rear axle shafts.
Another Classic Conundrum
I just got a 1954 IHC R120 4x4 3/4-ton pickup to restore/modify. I am thinking of putting 1980’s Chevy running gear under it to replace the stock stuff. Can you help me with any ideas?
Robert. L. Rhodes, Jr. — Via e-mail
Robert, I wonder if you know how rare a bird you actually have there. There were a total of 62, count ’em, R-120s built from 1953 though 1954. It was International’s first postwar light-duty 4x4. If it’s in good original shape, it could be worth as much as $7500 unrestored. Given the interest in old IHC trucks, your truck would be considered a real find to a ‘Binder enthusiast. I urge you to restore it or sell it to someone who will, but I realize it’s your truck and you can do what you like.
Getting Some Zees
I just bought a 2002 Chevrolet S-10 ZR-2. My questions: Is the ZR2 a good platform to build on and what problems should I expect with it? As it is now, how good an off-road vehicle is it without serious mods? I have already added a K&N Generation II performance kit, a Fabtech Prerunner bumper with a set of ProComp 100W lights, and front and rear two-inch receiver hitches to mount a winch when necessary.
Keith Brown — Via e-mail
Your ZR-2 comes with biggish 31-inch tires, a factory-lifted suspension, and a rear locker in an 8.5-inch axle. As stock rigs go, it’s ahead of the game. Is it built for high-adrenaline four-wheeling? No. A lot will depend on what you plan for it, trailwise. The weakest link is the front end. The ZR-2s have an enhanced front diff (iron housing instead of aluminum), but it’s still fairly weak. Also, the rear Eaton Locker (a.k.a. the “Gov-Lok”) is a marginal piece. Unless you want to pony up for a custom, solid front-axle conversion, here’s what I would do: Build around 33x12.50-15 tires. Superlift makes a six-inch kit for the ZR-2 that will accommodate those tires. I’d stay away from body lifts. For 33s, you’ll need a gear swap to 4.56:1 ratios, and, while you are at it, you might swap in a more effective locker. If you want transparency for the street, I’d recommend an ARB. There are many other choices as well, from limited-slips to automatic lockers. Your rear axle probably has 28-spline shafts, which can be upgraded by about 25 percent (or more) with 30-spline shafts. You can buy custom 1541h alloy 30-spline shafts for the rear (you’d need to then get the 30-spline version of the ARB). I’d stay with an open diff up front because it will keep it in one piece longer. There isn’t much available for it anyway.
Winch In The Way
I am rebuilding and upgrading my grandfather’s 1969 CJ-6. It’s a sound vehicle with only 70K original miles. Its biggest problem is the steering. It’s unpredictable and wanders down the road. I have checked out Advance Adapters’ steering conversion, but the problem is that the steering box mounts on the inside of the frame right where the PTO winch mounts. Any ideas or alternatives for making my Jeep safer and more steerable?
Mike — Via e-mail
Wanderitis is common for old Jeeps with bellcrank-type steering. With regards to the winch or the Saginaw steering conversion, I’m afraid I have to give you an either/or-you can have one or the other. First off, if all you want to do is reduce/eliminate the wanderitis, a rebuild of the steering system will probably do that, and a power-steering conversion alone might not. By a rebuild of the stock system, I would include the tie rods, drag link, steering box (probably only an adjustment needed, but it needs checking), the bellcrank assembly (often a big source of problems), and the steering knuckles on the axle (they have bearings inside that can get loose). If you get a decent older Jeep manual and read though everything, you’ll go back to stock performance. All the parts are available. As for the power steering, Advance’s is a good kit, and you’ll like it, but you’ll have to get shed of the PTO winch. PTO winches are cool and classy, but not particularly useful in the wheeling world because it’s difficult for one person to operate them safely. Depending on which brand of winch you have, you might find a willing buyer for it in the classic Jeep crowd, and that money could go a long way toward buying a conversion kit. If you do the steering conversion, I’d further recommend overhauling the knuckles, which also can be a source of wanderitis.
Big Plans
I’m looking at buying an old Chevrolet M1028 military truck. I have big plans. I would like to run the new 49x21-20 IROKs. Can this truck handle this or do I need to run smaller tires?
Dan Ames — Via e-mail
If all you want to do is cruise the fast food strip on Saturdays and show off, then, yes, that CUCV can handle tires that big. It will cost you a mint because you will be throwing half the truck away and designing a new suspension for it. The tires alone will probably cost more than the truck. If you want to ‘wheel the truck, I’d go with tires no bigger than 38s, a 10 inch lift and 5.13 gears (should be 5.38 but 5.13 is as low as you can find for the 14-bolt). You’ll need a ladder to get into the truck, but you’ll be able to ‘wheel it and you’ll still get plenty of attention cruising by Taco Bell.