Question: We have an '07 Wrangler Rubicon Unlimited with 35s and several hundred pounds of racks, winch, and gear. We tow a 3,500-pound camping trailer, but even with 5.13:1 gears, there just isn't enough power-really not even enough for daily driving without the trailer. I don't need to race anyone, but I do want to make it up hills. I need torque. Is there a turbodiesel swap that wouldn't require me to rob Fort Knox? Or another suggestion- maybe a blower?
Laguna Niguel, CA
Answer: Yep, you're right, that is the biggest complaint with the new JKs. The V-6 just doesn't make enough power. There are some headers available and an air filter change, but together, these really aren't gong to make the power you're looking for. I am sure in time that the aftermarket will be supplying a blower for the V-6. I understand that Adventure Innovations (805/322-7001, www.adventure-innovations.com is in the process of developing a supercharger kit for the JK and may have it available by the time you read this.
The problem is that most of the diesels you could swap will not make the power you're looking for, or would not meet emissions standards. Burnsville Off Road (www.burnsvilleoffroad.com) has made some conversions using the '07 3.0L Mercedes engine. A really nice engine, but my guess is it's also really expensive.
You also might consider putting your Jeep on a "diet" if possible. You are towing the Unlimited's absolute maximum rated load (3,500 pounds) and with bigger tires, "several hundred pounds" of bolt-ons, a full tank of fuel, and a couple of full-grown adults and their gear riding inside, you may well be exceeding the vehicle's gross combined weight rating, which really hurts both power and fuel mileage.
Question: Regarding "Lower Gears for Durango Axles" (Techline, Jan. '08):
The front axle of the '05 Dodge Durango in question is the Corporate Chrysler 8.0 (205 mm), not a Dana 30. They have been using this axle beginning with the '00 model year in the first-generation Durangos, and it has continued in the second generation as well. The earliest Durangos ('97-'99) used a Dana 35. I've seen up to 4.56:1 gearing available for the Corporate 8.0 with no change to the carrier required. I've heard this is the same front axle that is used in late-model Ram 1500s. I don't have any input on the strength of this axle.
The 8.25 is used in the rear, which I find interesting, being that the first-generation models (which didn't offer Hemi power) were available with the larger 9.25 axles.
By the way, what is meant by a "floating" axle? I tested my 9.25 and it sunk.
Answer: Yep, I blew it there with my answer. You're completely right. My only excuse is that I had some brain fade when I was in the process of answering three different letters on Chrysler axles and must have gotten my fingers on the wrong line of my gear chart.
Yes, there are some aftermarket 4.56:1 gears available from places like Randy's Ring & Pinion. The lowest factory gear is 3.92:1, and yes, the lower gears will bolt right up to the present carrier. And yes again, the Chrysler 8-inch is also used in the front of IFS Dodge 1500-series pickups starting in 2002.
As to the rear end, it could be either an 8.25 or the much stronger 9.25-inch with 31-spline C-clipstyle axles. Thanks for keeping me straight.
As to your question: A "full-floating axle" is one where the wheel is mounted to a hub with bearings on the inner and outer portions, which in turn rides on a hollow spindle that is either an integrated part of the axlehousing or bolted on. The spindle/hub carries all the weight, not the axleshaft. The axle is slid through the spindle and can be removed without taking the wheel off. In other words, the axle "floats" and carries no weight and just acts as a driver. This is common on 3/4- to 1-ton pickups.
On a "semi-floating" axle, the wheel is bolted directly to the axleshaft. The weight of the vehicle is carried on one bearing on the outer end of the shaft and by the differential assembly on the splined end of the axleshaft.