Local Jeep Transmission Repair Experts

The Advanced Transmission Center team is your go-to source for Jeep transmission repair in Denver. Jeep is one of the smaller manufacturers when it comes to market share in the United States, representing only 2.33% of the vehicles on the road in 2022. However, Jeep vehicles are very popular in Colorado, and their 4-wheel drive and all-wheel drive vehicles are common. Due to their outsized popularity, Advanced Transmission Center has plenty of experience servicing and repairing Jeep OEM parts, such as automatic and manual transmissions. We also handle transfer cases, differentials, and other driveline issues.

1990’s: A340 / AW4 Transmission Problems

Jeep has a history of using other companies’ driveline components in their vehicles rather than building something of their own. Many older Jeep vehicles use the A340 transmission, which Jeep calls the AW4. The A340 / AW4 is built by Aisin Warner, a company that specializes in building driveline components for a number of automotive manufacturers. The A340/AW4 is a 4-speed automatic transmission that is electronically controlled and has a 2-speed 4WD transfer. Jeep used this transmission in the Jeep Cherokee from 1987-2001, the Jeep Grand Cherokee in 1993 and 1994, and the Commanche from 1987 until 1992. It has been popular because it is a very easy-to-use transmission, especially shifting into and out of 4-wheel drive. Making the transmission more driver-friendly has, of course, meant that there are some issues that need to be kept in mind.

Given the large number of vehicles this transmission is used in, it is no surprise that there are known issues with the AW4 transmission. Some of those are listed in the table below.

Common AW4 Problems

1. Many drivers have complained of delayed shifting, especially when going from Park into Reverse or from Reverse into Park.
2. Transmission noise is another complaint, with some experiencing torque converter chatter and others getting noises when the vehicle is shifting between gears.
3. It is also not uncommon for the transmission to lose forward or reverse gears completely. These complaints have many possible causes, but there are known weaknesses in the 2nd gear sprag assembly and with the torque converter clutch.

In applications where the driver is doing a lot of mountain driving or towing, there are upgrades available in order to handle the greater stress placed on these components. The AW4 was used in some of the most popular Jeeps in the 1990s, and Advanced Transmission Center has plenty of experience diagnosing and repairing these issues.

2000-2010’s: 42RLE and 722.6 Transmission Problems

Jeep used the 42RLE transmission in a number of its vehicles. The original transmission had been used in front-wheel drive vehicles and was redesigned to be used in rear-wheel-drive applications beginning in 2003. It has been used in the Jeep Liberty starting in 2003, the TJ Wranglers from 2003 through 2006, and the JK Wranglers from 2007 through 2013. Built by Chrysler, the 42RLE has the unfortunate reputation of being the most unreliable transmission that Chrysler ever built.

There have been a number of problems with the 42RLE, some of which have relatively easy fixes and others that don’t. For instance, drivers might find very erratic shifts or very hard shifts as the transmission bangs into gear. In some cases, this is actually caused by a faulty wiring harness connecting the transmission control unit to the shift solenoids. A replacement of the wiring harness plug can fix this particular problem without the need for costly transmission repair. However, that very same hard shifting can be caused by wear in the valve body. These valve body issues are well-known in the 42RLE and will likely require a rebuild of the transmission. Make sure that you bring your Jeep to a transmission specialist in order to make sure that the right fix is found for your vehicle!

The 722.6 transmission is a 5-speed electronically controlled automatic transmission designed and built by Mercedes. In Chrysler applications (which includes Jeep), the transmission was called the NAG-1. As one might expect from a unit designed by Mercedes, the 722.6 / NAG-1 transmission has a reputation for being well-built. Jeep used this transmission in the 2006-2011 Jeep Commander, the 2006-2013 Grand Cherokee, and the 2011-2014 Jeep Wrangler. While the NAG-1 was a sturdy transmission, it did have some known issues that Jeep owners have had to contend with.

One design flaw that creates a lot of transmission issues in these vehicles is the conductor plate within the transmission. The conductor plate is mounted internally to the valve body and has a number of sensors and electronic components that control the shifting of the transmission. The conductor plate will begin to crack and pick up contamination within the transmission over time, which causes the electronic controls to malfunction. Shifting issues will pop up that will eventually cause the vehicle to go into “limp mode,” where the vehicle will not shift out of a particular gear in order to save the transmission from further damage. Drivers experiencing these issues will need to get their Jeep into their local transmission shop as soon as possible before more serious damage can occur. 

’20s and Beyond: ZF9HP Transmission Problems

Jeep became the first manufacturer in the world to bring a 9-speed automatic transmission to market in a passenger vehicle when it introduced the 2014 Jeep Cherokee. Since that introduction, Jeep has used the ZF9HP for front-wheel drive and all-wheel drive applications in the Cherokee, the Renegade, the Compass, and the Grand Commander. Built by the ZF Group in Germany, the ZF9HP is a very modern transmission design that has done away with traditional clutch packs and instead uses a patented design called “dog clutches.” While the ZF9HP has been very popular and can also be found in Chrysler, Land Rover, Honda, and Nissan vehicles, it has had its share of problems that Jeep owners need to be aware of.

From the very introduction of the unit in 2014, some Jeep owners have complained of slow or delayed shifting. There have been several technical service bulletins issued that recommend reprogramming the onboard electronics in order to deal with these issues. However, this has not solved the problems in all cases. While the software upgrade can smooth out shifting overall, the 2nd to 3rd gear shift has been a problem for many drivers who feel the vehicle bangs into 3rd gear. Drivers have also found that shifting while driving at highway speeds seems to be fine, though driving in town can result in extremely erratic shifting in stop-and-go traffic.

Manual Transmissions: 4-speed, 5-speed, and 6-speed Problems

While manual transmissions can seem pretty bulletproof compared to an automatic transmission, that doesn’t mean that they can’t have issues. Jeep has been using manual transmissions since their origins 80 years ago, and most recently, they have offered a German-built 6-speed manual transmission called the NSG370 in the 2005-2008 Jeep Liberty and the Wranglers from 2005 to present. Jeep drivers with the 6-speed manual transmission are very likely to face a number of problems that they will need to keep an eye on.

The most serious and heavily reported complaint about this 6-speed manual transmission is overheating and failure of the clutch pressure plate. Many drivers have found while operating the vehicle under load that the clutch will get hot enough to cause the plate to “explode.” Not only can this damage the rest of the transmission, but it can cause a fire hazard when overheated parts and pieces fall on the ground under the vehicle and potentially start fires. The issue was serious enough to force Jeep to recall a large number of vehicles equipped with this transmission. If you drive a Jeep with a manual transmission and are having issues, bring it to the transmission experts at Advanced Transmission Center as soon as possible.

Jeep Driveline Maintenance and Repair Specialists

In Colorado, drivers routinely depend on Jeep all-wheel drive and 4-wheel drive vehicles to negotiate roads during bad weather. This, of course, adds a transfer case as well as a front and rear differential to the list of driveline components that a driver needs to keep maintained. Due to the complexity of electronic control systems, most general automotive repair shops simply don’t have the tools or training to diagnose or repair driveline issues. 

Advanced Transmission Center does Jeep repairs in Denver. We have been providing service and repair for Jeep trucks and SUVs since 1986 and have the training and expertise to handle routine maintenance of your 4-wheel or all-wheel drive systems. We can handle any transfer case, front differential, and rear differential repairs you may need because we are the Jeep repair specialists near you.

Jeeps are very common on the roads in Colorado and have definitely evolved over the years. The old 3-speed manual transmissions have been replaced by electronically controlled 9-speed automatics and 6-speed manual transmissions, and these units have their own quirks and issues that require a driver’s attention as part of their routine vehicle maintenance. Advanced Transmission Center has kept the pace by continuously training in the latest diagnostic and repair strategies for these vehicles. Don’t trust your valued Jeep to a general automotive shop. If you’re looking for Jeep transmission repairs near you, call either our Lakewood or Westminster shops today to get all of your Jeep driveline needs taken care of!