Please let me know also... Jeep is going in this Friday for service - I am trying to gather as much info as possible to bring to them when I sit down with the techs. I have drafted a letter to the Service Manager based on several postings here on JeepGarage concerning this issue that many of us are having with the 2011-2012 WK2 Overland Hemi QT2 builds. I hope it saves them some time in diagnosing this issue in my case. Here is the body of the draft letter so far:
(No grammar Nazi's yet please...)
Noticeable Engine Shudder Problem
I purchased my 2012 Jeep Grand Cherokee Overland Summit with the 5.7L Hemi engine, and Quadra Trac 2 drive from your dealership on January 15, 2012. The build date on the vehicle is 11/2011. The VIN # is XXX.
The Jeep is in for service today because of the major problems I am currently experiencing with “transmission shudder” and engine performance that is described further below.
Between 45 - 70 Mph, the Jeep physically stammers/misses/wobbles when maintaining a speed, while under slight acceleration but especially when incurring a slight incline. My word for the problem would be “shudder.” I have about 3700 miles on it now and it seems worse at times on the same roads and under similar weather conditions I have been driving for over month. This problem has simply reached an unacceptable level for me. The issue concerns us greatly as we have used the truck mainly for long commuting trips and the Jeep is quickly becoming probably the worst performing vehicle have ever driven. Not exactly what we had expected in a $40K+ vehicle.
Since new, while accelerating, the truck stutters as if the engine was "missing a beat"/ or had a cylinder misfire. This problem happens when accelerating at about 20% throttle, and teh engine tries to shift down a gear. It runs so poorly as if it has a bad spark plug and clogged injectors all while on an unbalanced wheel or tire. Even on the on the newly paved portions of the freeway it feels like we are “driving over a washboard.“ I have tried both 87 and 89 octane gas in the vehicle and it the problem remained a constant issue.
We have observed the following problems:
- The Jeep will shudder when slightly accelerating (not requiring downshift) for 2-3 mph on the highway in overdrive. When driving around the beltway, it happens at 60 mph consistently after I let off the gas and then give it just enough gas to maintain speed. When I push a little more on the gas and the “choking” sensation goes away, though the shudder is still there. The sensation happens on both hills and flat terrain.
- The problem persists at all speeds when accelerating from 45 mph to 90mph (did not try any faster). The RPMs appear to always be under 2K when it happens. I have tried different transfer case modes (auto vs. sport), with the tow/haul mode engaged and anti-skid mode on and off.
- Additionally, when accelerating from a stop, while there is no shudder, there is a noticeable “dead spot,” or drop in acceleration when starting to accelerate from a stop in 1st gear into 2nd. The transmission seems to buck, like it was confused if it wanted to change gears or not. It definitely does not shift smoothly, and is getting rather annoying.
While researching these problems online, the “transmission shudder” problem seems to be prevalent in the 2011-2012 Jeep Grand Cherokee (WK2) Overland/Summit models with the 5.7L Hemi engine. Many contributors have had their torque converters replaced, PCM flashes performed (fixes some issues), mounts replaced, and tires rebalanced in an effort to have this issue resolved. Several people have reported that a Chrysler Star Case has been opened for their individual problems, though I have found no official TSB that has been released to cover this exact problem in the 2012 models yet. Many are getting frustrated with their new vehicle’s performance as am I.
I found several postings from online Jeep forums that mirror the problems I am experiencing and that I have included below, and attached to this letter that may be a starting place for the technicians:
PCM Software Flash
- “My problem is a shudder at slow speed usually when the truck was slowly moving when you took your foot off the accelerator it felt like the truck jumped back up to another gear. It also happened when merging onto the highway and you took your foot of the accelerator once you got up to speed I could feel a shudder in the pedal/body. The fix also has cured the dead spot in the accelerator everyone talks about.” The recall code is Rapid response code 11-038 PCM TCM Improvement.
- “Fixed it!!! - “I have a 2011 5.7 and mine has had the exact same issues as listed. My dealer received a Star Case and it was applied two days ago. (2/20/12) What they did was “add an isolator in the front differential,” it was in the shop for a day and a half (they said it was a major job). Low and behold they actually fixed it!!!” (No details of fix included)
- A drive shaft dampener installed in another Jeep which seemed to fix the problem.
In addition to the shudder problem mentioned previously above, I would like you to remedy the other following issues: ......
I'll let everyone know if we get it fixed, exact part numbers, patches etc..