As the 2014 Jeep Cherokee continues to make the rounds on the market, it’s high time we take a closer look at the SUV and learn more about its development. No matter which side of the love-hate spectrum you currently occupy regarding the latest generation, there’s no denying that the Power Transfer Unit, or PTU, on the Cherokee has been a milestone in automotive engineering for the automaker.
Speaking in the video above is Michael Kirk, director of Manual Transmission, Driveline & Axle Engineering for Chrysler. It all started, as Kirk states, with the Dodge Dart’s FWD chassis, and the “problem of trying to create a vehicle with … a front-wheel-drive-based architecture that would have the same capabilities that the Jeep customer would expect for off-roading.”
As Kirk recalls, the engineers started with creating a drivetrain that utilized a low-range transfer case inside the PTU. “We went out and we tried that, and we said, ‘You know, we really need more torque on the rear end of the vehicle.’ So, we ended up splitting and putting the low-range planetary in both the PTU and the [rear differential module],” states Kirk.
What resulted was a drivetrain that operated with a front-mounted transfer case, linking front and rear drive axles with a dog clutch that could be engaged at the push of a button to deliver a 52:1 crawl ratio. “It’s right in the same range of what the Wrangler has,” Kirk remarks. Add to that a rear mechanical locking differential, and a solution for the 2014 Cherokee’s off-road quandary was reached.
Chrysler took the time to celebrate the team that developed the PTU for the Cherokee, giving them the Walter P. Chrysler Award earlier this year. It’s only fair that we do the same in our own way, and share how meaningful of an achievement this was, not just for Jeep, but for the automotive engineering geek in all of us.