Letter Of The Month
Cheap Jeep!
Question: I have a late '80s Jeep YJ and I am looking to run 35-inch tires. I am wondering if a spring-over swap with mid-'80s Chevy 3/4-ton running gear (Dana 44 front, Corporate 14-bolt rear) would be possible or even make sense. I'm thinking cheap, as all I am going to do is beat on it, so please give me a push in the right direction.
Russ W, owner of the Redneck YJ
via 4wheeloffroad.com
Answer: You are on the perfect course for a great Cheap Jeep build. Here is what you'll need. First is a full-width axle swap kit to push the leaf springs outboard of the frame so they line up with the GM spring mounts. Poison Spyder Customs (303.777.4820) or Blue Torch Fabworks (334.673.2755 www.bluetorchfab.com) offer them if you can't fab your own. You can reuse your stock leaf springs, but you may want to get an antiwrap bar for the rear such as those offered by Sam's Off Road (800.446.5503) since YJ springs are soft.
Also look into a crossover steering kit, which may require a flat-top passenger Dana 44 knuckle and high-steer arm, but will be better for off-road use. Your transfer case has the front output on the wrong side, so track down a Dana 300 and the appropriate adapters if need be and you'll be in business since your GM Dana 44 diff is on the passenger side.
The 35-inch tires are a little small for the massive Corporate 14-bolt, but I wouldn't go any bigger than 37s on the front 44. In fact, 36-inchers would probably be ideal. However, if this is a street-driven ride you made need some massive fender flares since the tires will be sticking out a bit.
I think this is a great low-buck buildup. YJs are cheap these days, yet have stout frames and many have the torque of the inline-six. Spring-over leaf-spring suspensions are proven and can take a ton of abuse. The eight-lug 3/4-ton GM axles can be had for less than most Dana 60s, but allow you to easily upgrade to a 60 in the future without changing wheels. And with the addition of a good locking differential or two, you'll be wheeling 95 percent of the trails with no problem. I like your plan so much I'm giving you the Tech Letter of the Month, and since Eaton/Detroit Locker (800.328.3850, www.detroitlocker.com) is sponsoring it this month, you'll be getting a free locker of your choice for your project Jeep. I'd recommend a Detroit Locker for your 14-bolt. They are rugged to the core, and I can't say I have ever seen one break. Eaton also offers its cool Electrac for the Dana 44, which acts like a limited slip when it's open and a full locker when it's electronically locked.
Two-Axle Drive, or Four-Wheel Drive
Question: I have been around trucks since I can remember and will probably own nothing else till I die. However, I admit I don't know everything about them. When it comes to the front axle I start getting lost. If you shift the transfer case to 4WD, why do you still have to engage the front hubs (if manual) for the front wheels to pull?
What occurs if the hubs are engaged but the transfer case is in 2WD?
Clinton
via 4wheeloffroad.com
Answer: First, realize that putting your transfer case in 4WD only engages the front axle, as you always have drive going to your rear axle via the driveshaft. When you lock your front hubs it basically attaches each front wheel to the axleshaft inside your front axlehousing. Locking hubs are designed so your front axleshafts and driveshaft do not spin while on asphalt, thus helping your fuel economy. If you don't lock your hubs, but you engage 4WD in the transfer case, the front axleshafts will turn via the driveshaft, but the front tires will not. If you lock your hubs but don't engage 4WD in your transfer case, the turning of your front tires as you roll down the street or trail will turn the axleshafts and your front driveshaft, but no power is getting to these tires. Thus when you come against a rock or obstacles they will not help pull your truck up and over it because you are still in 2WD. You need to engage 4WD in the transfer case and lock your hubs to get power to your front tires.
To complicate things further, I'll mention lockers and open differentials. If your axles have open differentials, the power always tries to go to the tire with the least amount of traction. And if one tire has no traction because it's off the ground or in mud, it will spin while the other with traction does nothing. By engaging 4WD you are sending power to the front and the rear axle, but if both have open differentials you really only have two-wheel drive, one front, one rear. By installing a locker or limited slip in the differential you are more evenly splitting power between both tires on that axle, and with a locker front and rear you are getting true four-wheel drive. I think it should be thought of like this: The transfer case engages the driveshafts to the axles, lockers engage the axleshafts within the axlehousing to the hubs, and the hubs engage the wheels at the end of the axles.