2015 Jeep Grand Cherokee Transmission Issues: Symptoms and Recall Guide
You put the gear selector in “Drive,” but nothing happens. You try again—still nothing. Then you realize the electronic shifter didn’t actually register your command, and now you’re stuck with a line of cars behind you.
The 2015 Jeep Grand Cherokee’s transmission is a major pain point for owners. The primary issue isn’t a clunky gearbox—it’s an electronic shifter design that can trick you into thinking the vehicle is in Park when it isn’t. This flaw led to a major recall affecting over 800,000 vehicles. On top of that, rough shifting, delayed engagement, and error codes like P0734 are common complaints with known software fixes.
TL;DR
The 2015 Grand Cherokee uses a ZF 8-speed automatic transmission with an electronic “monostable” shifter that always returns to the same position. This design caused drivers to accidentally leave the vehicle in gear, leading to rollaway accidents. Jeep issued recall S27 to address this with a software update. Other common issues include rough shifting, sluggish engagement, and code P0734 (Gear 4 incorrect ratio)—often fixed by a dealer-performed TCM software update, not a costly rebuild.
Key Takeaways
- Shifter recall is the biggest safety issue: The monostable shifter doesn’t provide physical feedback, so drivers thought they were in Park when they weren’t. Over 42 injuries were linked to this defect before the recall.
- Rough shifting is common: Many owners report jerky shifts, especially between 1st and 2nd gear at low RPM.
- P0734 code often means software, not hardware: TSB #21-027-15 REV-C addresses this with a TCM flash costing $150–$250—much cheaper than a transmission rebuild.
- Communication faults can leave you stuck: CAN bus network issues can prevent the transmission from shifting out of Park.
- Check your recall status: The S27 recall is free. Dealers will update the software to prevent rollaway risks.
The Big One: The Electronic Shifter Recall (S27)
Here’s the situation. The 2015 Grand Cherokee doesn’t have a traditional mechanical shifter. Instead, it uses a monostable gear selector—you push it forward or backward to select a gear, and it springs back to the same central position every time. No matter if the Jeep is in Park, Reverse, Neutral, or Drive, the shifter always looks identical .
Why is this dangerous? Because drivers thought their vehicle was in Park when it wasn’t. The shifter’s design made it easy to accidentally leave the Jeep in gear, and the warning chime wasn’t always enough to alert you. The result? Vehicles rolling away, sometimes with drivers outside the car. At least 42 injuries were linked to this defect before the recall .
The recall: Chrysler (FCA US LLC) recalled 811,586 vehicles, including 2014-2015 Jeep Grand Cherokees with the eight-speed automatic and monostable shifter . The fix is a software update that prevents the vehicle from being shifted out of Park without the driver’s foot on the brake and improves the warning system . Dealers perform this update for free.
How to check: Contact a Jeep dealer with your VIN, or call Chrysler customer service at 1-800-853-1403 . The recall began on June 24, 2016—so if your 2015 Grand Cherokee hasn’t been updated, you need to get this done.
Other Common Transmission Symptoms
Rough or Delayed Shifting
This is one of the most frequently reported problems. Owners describe the transmission as sluggish, with improper shifting, jerky transitions, or difficulty engaging Drive or Reverse . A common pattern: rough shifts between 1st and 2nd gear at around 1,500 RPM .
Why it happens: The ZF 8-speed transmission uses adaptive learning. It adjusts shift points based on your driving style. But early software calibrations were problematic. In some cases, the transmission just needs to “learn” your habits—some owners report the rough shifting smooths out after a few thousand miles . In other cases, a dealer-performed software update (detailed in TSBs) is required.
P0734 Code: “Gear 4 Incorrect Ratio”
This diagnostic trouble code means the Transmission Control Module (TCM) detected a problem with the 4th gear ratio—the transmission slipped or didn’t engage properly . The code may be accompanied by the vehicle getting stuck in 4th gear (limp mode).
Here’s the good news: For the 2015 Grand Cherokee, P0734 is very likely a software issue, not a hardware failure . Jeep released Technical Service Bulletin #21-027-15 REV-C specifically to address this with a TCM software update. A dealer flash typically costs between $150 and $250 . Do not let a shop talk you into a $4,000+ rebuild before verifying if this TSB has been performed.
Stuck in Park Due to Communication Faults
The electronic shifter relies on the vehicle’s CAN bus network to communicate with the TCM. When communication fails, the transmission may refuse to shift out of Park. One documented case involved a 2015 Grand Cherokee 3.6L that suffered from communication network faults that would leave the transmission stuck in ‘PARK’ .
The fix: A skilled technician can diagnose the CAN bus waveforms to isolate the faulty node—typically either the TCM or the Electronic Shifter Module (ESM). Replacing parts arbitrarily is not recommended .
Transmission Fluid Leaks (Cherokee Recall, Not Grand Cherokee)
Note: A separate recall affected the 2021 Cherokee for transmission fluid leaks, but the 2015 Grand Cherokee is primarily affected by the shifter recall and engine-related issues like a faulty crankshaft position sensor .
Transmission TSBs at a Glance
| TSB Number | Issue | Fix |
|---|---|---|
| S27 Recall | Monostable shifter—risk of rollaway | Software update (free at dealer) |
| 21-027-15 REV-C | P0734 code (Gear 4 incorrect ratio) | TCM software reflash ($150–$250) |
| 21-003-14 REV. A | Rough shifting between 1st and 2nd | Transmission adaptation learn procedure |
| 21-012-14 | Shift quality concerns | Transmission Adaptation Drive Learn Procedure |
| 21-003-25 | Rough shifting, loss of propulsion (applies to 2023 WL models, not 2015) | TCM software update |
Owner Experiences: The Good and The Bad
The frustration is real. One owner wrote a scathing review of the electronic shifter:
“I strongly suggest that you should not purchase one of these vehicles until the terrible, dangerous, unreliable, finicky electronic shift program is changed. Every time I start this Jeep and pull back the console shift lever to put it in drive, nothing happens the first time. I have to repeat this action twice to get the transmission into Drive” .
Another owner reported the recall done but still experienced issues: “The Jeep would sometimes still be in D when people thought it was parked. I almost rolled forward and hit their car” .
On the flip side, some owners find the issues resolve themselves. One noted: “I too had this problem on my 2015, I am now on 3100K miles and the problem has been gone for about 500 miles or so. Maybe it is simply the learn process the new transmission needs to have” .
What to Do If You’re Experiencing These Issues
- Check your recall status—Call Jeep with your VIN to confirm if recall S27 has been performed. It’s free and covers the rollaway risk.
- If shifting is rough or sluggish, try driving conservatively for a few thousand miles to let the transmission adapt. If the problem persists, ask your dealer about TSBs.
- If you have code P0734, ask your dealer about TSB #21-027-15 REV-C. A $200 software flash is the most likely fix—don’t let anyone sell you a rebuild yet .
- If you’re stuck in Park with no warning lights, a CAN bus communication fault could be the culprit. Have a technician with advanced diagnostic tools (like wiTECH) check the network .
- If your transmission fails completely (like one owner who had 85,000 km on their Jeep when the transmission “blew”), consider contacting Jeep head office—they may meet you halfway on repair costs, especially if the vehicle has a full service history . A transmission specialist may also offer a cheaper replacement than a dealership .
FAQ
1. What is the transmission recall on the 2015 Jeep Grand Cherokee?
Recall S27 addresses the electronic “monostable” shifter that could trick drivers into thinking the vehicle was in Park when it wasn’t, leading to rollaway accidents. A free software update fixes it .
2. Why does my 2015 Jeep Grand Cherokee shift rough between 1st and 2nd gear?
This is a common complaint. It may be the transmission’s adaptive learning process (it sometimes smooths out after a few thousand miles) or a software issue that a dealer can address with a TCM update .
3. What does code P0734 mean on a 2015 Grand Cherokee?
P0734 means “Gear 4 Incorrect Ratio”—the TCM detected a problem with 4th gear. For this vehicle, it’s most likely a software issue, fixed by TSB #21-027-15 REV-C with a $150–$250 dealer flash .
4. Is the 2015 Grand Cherokee transmission reliable?
Owner reviews are mixed. The ZF 8-speed itself is a robust transmission, but early software calibration issues and the controversial electronic shifter design caused significant frustration and safety concerns .
5. How much does it cost to replace a 2015 Grand Cherokee transmission?
A dealership replacement can cost nearly $14,000. However, in many cases, a much cheaper software update (around $200) resolves the issue. Always get a proper diagnosis before authorizing a major repair .
6. My transmission won’t shift out of Park. What could be wrong?
A communication fault on the CAN bus network can prevent the electronic shifter from talking to the TCM. A technician can diagnose which node (TCM or ESM) is failing .
7. Can a transmission flush fix my shifting problems?
Possibly, if the fluid is low or dirty. But for the 2015 Grand Cherokee, software issues are the most common cause of shifting complaints. Have the TSBs checked before paying for a fluid flush .
For Further Reading:
Sources and More Info:
- NHTSA Recalls Database (Search by VIN)
- Car Complaints: 2015 Jeep Grand Cherokee
- Edmunds: 2015 Jeep Grand Cherokee Owner Reviews
Prices and specs are subject to change. Always consult official sources and your owner’s manual for the most accurate and up-to-date information. Repair costs may vary by region and shop.
Have you dealt with transmission issues in your 2015 Grand Cherokee? What fixed it for you? Drop your experience in the comments below.
