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Wednesday 23 August 2017
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Closer Look: The Jeep 9-Speed Transmission

Closer Look: The Jeep 9-Speed Transmission

We had a caller on last Saturday’s Car Pro Show wondering about the Jeep Cherokee 9-speed automatic.  Luckily, Cars.com has one in their long-term review fleet. Here is their report:

One of the most ambitious features of the Jeep Cherokee’s rebirth in 2014 was its standard and highly technical nine-speed automatic transmission from ZF Friedrichshafen AG. In fact, one of the reasons Cars.com purchased the redesigned Cherokee as a long-term test car was to test this new unit during a year of driving.

The nine-speed is big news for lots of reasons. First off, it’s innovative: The Cherokee is one of the only SUVs to use such a transmission, and to cram nine gears in the limited space of a front-wheel-drive transmission, it uses a unique construction. Secondly, the transmission delayed the Cherokee’s launch for months as Jeep worked out powertrain programming issues.

After 14,000 miles of owning a four-cylinder Cherokee with all-wheel drive, here are nine things observed about the Jeep’s nine-speed automatic transmission:

It Truly Drives Like a Six-Speed

One of the most common questions received about the nine-speed auto is whether it’s always shifting, given the high number of gears. Not at all, in fact. The nine-speed does a great job hiding its gear count and for the most part doesn’t give much indication it has that many gears. The 6th, 7th, 8th and 9th gears are all overdrive gears, and the top two engage at brisk highway cruising speeds.

The Nine-Speed Pairs Better With the V-6

The Cherokee’s 184-horsepower, 2.4-liter four-cylinder has trouble powering through some of the transmission’s quirkiness. Whereas the V-6’s extra grunt makes up for an ill-timed upshift, the modestly powered four-cylinder runs out of steam when the transmission upshifts too soon, like it often does from 1st to 2nd gear.

Untimely Shifting

In Auto mode, it’s nearly impossible to predict when the transmission will have a good or bad day. Sometimes the Cherokee shifts perfectly and matches the four-cylinder’s power band with ease, but there are bad days when the car immediately shifts into 2nd gear from a stop and then drags it out and clunks into 3rd.

Lackluster Software Updates

We didn’t just complain about the transmission. We also took the Cherokee to the dealership multiple times and a technician applied corrective software updates. There were marginal improvements in the fluidity of the shifting, but even the latest transmission and engine computer flashes couldn’t shake the nine-speed’s biggest problem areas.

Sport Mode Mitigates Some Issues

Of the Selec-Terrain driving modes — Auto, Snow, Sport and Sand/Mud — Sport mode uses aggressive shift programming and actually hides a lot of the awkward nuances of Auto mode. Later shifts and more even-keeled shift programming keep momentum going. The downside is the transmission holds gears aggressively before upshifting, so the engine speed hangs high between shifts.

Bangs Into Third Gear

One of the most consistent irregularities with the nine-speed transmission is its harsh shift into 3rd gear. Most gear changes smoothed out with the software update, but 2nd to 3rd remains an issue, as 2nd gear winds out a little too long and then — bam! — the car lurches into 3rd gear. The jolt is so hard that passengers often take notice.

Most Erratic in City Driving

As you’ve likely noticed, the Cherokee gives the most trouble through the first three gears, which makes city driving painful from stoplight to stoplight. After the car shifts into 4th gear, the experience is much less random and it drives like most other compact to midsize SUVs.

Most Relaxed During Highway Cruising

Once above 40-mph or so, the transmission chills out and starts to act like a normal gearbox. The car downshifts expectedly when the time comes to pass and will cruise along just fine at highway speeds and on road trips, even with the pokey four-cylinder. The Cherokee was a road-trip favorite over the summer and hit its 31-mpg highway rating with steady cruising. Jeep says the nine-speed is good for an extra 2 mpg compared to a traditional six-speed transmission.

Auto Stick Manual Mode is Limited

With the Auto mode sometimes producing irregular responses, the manual mode seemed like a good way to get the car in the correct gear. Unfortunately, the response time is slow between when the gear is selected and engaged, plus the computer is extremely protective and limits gear choices. While not uncommon, there’s much more lag time and overbearing control than in a Mazda CX-5 or Toyota RAV4.

Photo Credit: Jeep