EXCLUSIVE: Wrangler Chief Engineer Jim Issner Responds!

Date 2006/4/27 21:29:47 | Topic: Wrangler

After a long wait, 2007 Jeep Wrangler Chief Engineer Jim Issner has responded to your questions....

1. Can you elaborate on some of the technical changes being made in the 2007 Wrangler? For example, what changes are being made to the drive train and running gear to improve handling and off-road capabilities? What improvements are being made in the 4-wheel drive system to surpass the capabilities of the TJ?
The T case is stiffer and the main case joint is clamped by 18 fasteners instead of 9 previously. The t case consists of three pieces instead of five to reduce the potential for leakage. The largest improvement in capability over the TJ is in the new ETC (electronic throttle control). With the new electrical architecture, the powertrain module knows when the vehicle is in low range and we have developed a unique low range calibration for crawling. In addition, with ESP standard, all vehicles will have BLD (Brake limited differential) which can detect wheel slip and transfer torque to the other wheel with traction. This will provide an increase in capability for vehicles with open differentials.

2. We received a ton of questions about the Wrangler engine choices. With the 2007, we know the power plant will be different compared to the existing TJ. How was it decided to use the 3.8L V-6 as the main engine? What improvements are being made to the V-6 to accommodate the Wrangler? With the current gasoline issues in the U.S., do you anticipate an alternate power plant like a diesel engine or something else being offered in the future?
The new 3.8-liter V-6 engine is more efficient, provides a better torque curve and is quieter than the 4.0-liter I-6 engine. Overall, the 3.8-liter engine provides a better driving experience both on- and off-road. The 3.8-liter V-6 engine is basically the same (application on other products) but has been adapted to the Wrangler for a "north-south" application. This included a new front cover, accessory drive, exhaust manifold and oil filter location change. The oil capacity was also increased to 6 quarts to meet Jeep requirements for engine lubrication.

3. The Bumpers: What is 'blow molding'? Are the bumpers plastic to the ends or is there a solid core that extends out under that plastic? Also, how easy will it be to get a winch onto these new bumpers? How easy will it be to attach aftermarket bumpers?
Blow molding is a process where air is injected into a molten plastic to "blow it" into it's final shape. The bumpers are plastic to the ends and the bumpers are easily unbolted from the body. The stock bumpers will not support the addition of a winch but Mopar will offer one that does and is designed specifically for the new Wrangler.

4. Why did Jeep stick with a part-time 4-wheel drive system instead of a lockable/openable center differential configuration (full-time system)?
Customer feedback over the years has shown that our customers prefer a selectable system.

Check back on Monday for the rest of the interview...

(just kidding - the rest are after the jump...)

5. What height can the new Wrangler be lifted without having to change the driveshafts or swapping the cv-joints for u-joints?
We don't know since we do not produce or test lifted vehicles.

6. I didn't want to paraphrase this next question, it comes from one of our readers with the nickname, 'disturbed': "The number 1 question I have is WHY OH WHY DID YOU GUYS STICK A D35 UNDER THIS THING? This is THE most hated Jeep/Dana axle assembly ever produced and to continue to use it under the entirely new JK platform (even with upgrades) is mind-boggling. The D44 or AAM equivalent should have been used across the board for all JKs."
The Dana 30 front axles have a high pinion design (TJ was a low pinion design) to provide greater gear strength, the housing is stiffer and stronger, and the pinion bearings are larger for improved durability.The Dana 35 rear axle also has a larger pinion and unitized wheel bearings. The prior design had an on-shaft bearing. The axle shafts have also increased in cross section for improved strength. Overall, the axles have been improved over its predecessor. In fact, we are considering different names for the axles since they are virtually all new.

7. Why was the decision made to discontinue the 'Jeep' stamp (or as many people now call it, the 'Joop' stamp) in the body tub? That's been a signature part of the Jeep Universal design since the first CJ5's.
This was a styling decision. The chrome Jeep badge was added to the front grill to fall in line with our other Jeep products.

8. Do you see the JK-platform spawning any other Jeep vehicles aside from the two-door and four-door Wrangler variants. Namely are there plans for a pickup variant?
Not at this time. Unfortunately, we are not able to discuss future products.

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