What benefits come from 68RFE Tuning?

The 68RFE transmission provides some improvements over previous automatic transmissions matched with Cummins pickup trucks.  With 6 gears equipped to help with fuel mileage the new(er) transmission has some other improvements.  When these transmissions rolled out in 2007.5, they were the first diesel specific transmission developed by Chrysler.  Finally they had stepped up the filtration and moved away from bands being used internally.  All in an effort to extend service intervals, increase reliability,  and drive down maintenance cost.  The dual face torque converter clutch and integrated tow haul capability made the 68RFE a truly solid option for diesel truck owners.  

Other Articles About Cummins Tuning:

• 7 Things to Know When Tuning Your 2013+ Cummins
• Smarty MM3 Beta Stage 2
• '04 Cummins Tuned w/Smarty MM3

However, it is not without its faults.  One major flaw that every 2019+ 68RFE comes with from the factory is the UD purge test. The UD purge test, used in 2019+ 68RFE transmissions, can cause issues like excessive wear, overheating, and lubrication problems when left active, leading to potential long-term damage and reduced performance, especially under heavy loads. This test was mistakenly left active on 2019+ Cummins equipped with the 68RFE.

TCM (Transmission Control Module) tuning can address these problems by deactivating the UD purge test, preventing unnecessary stress on the Underdrive clutch system and improving overall transmission function. By reprogramming the TCM, you ensure that the transmission operates within its optimal parameters, thus extending component life, enhancing performance, and providing a smoother driving experience.

Another common problem 68RFE equipped Cummins is how they handle additional power. Once the power is turned up past the 450hp mark on these trucks, owners often experience a range of failures from burnt up clutches to ballooned converters and more.  Our transmission tuning aids those who are looking to add more power by electronically increasing your stock line pressure of 165psi to 175psi. This allows for much better clutch holding capacity and allows us to be able to support a 475hp ECM tune for 4th and 5th gen 6.7L Cummins trucks. 

While some of these failures can be attributed to mechanical abuse matched with aggressive tuning, we more often than not see well taken care of trucks suffering from the same issues. Like any other mechanical part in a truck they can fail.  The real problem with the 68RFE lies in the factory calibration.

Shifting:  Most people report that their truck seems to sit at 3,000 RPM while the speedometer slowly climbs.  Then 4th gear hits and the torque converter locks, bringing down the RPM and rapidly applying power to the ground.  In general shifts feel soft, like a slush box.  Even guys towing have found issue when trying to get around a slow vehicle on the highway.  It really comes down to the truck feeling unresponsive.  

Chrysler 68RFE Ratios

This is an easy problem to address.  Now with multiple custom tuning options available many of the 68RFE complaints can be addressed without sacrificing reliability. Adjusting shift points allows for stretching the wide torque curve provided in the 6.7L Cummins.  This also makes the truck feel more powerful.  Getting rid of the short shifting and really using all of the power.  Dialing in the torque converter lockup strategy gives these trucks the ability to put horse power and torque to the ground.   This is the best advantage to tuning a 68RFE transmission.  With a good custom tuning calibration the truck will finally feel the way you would expect 360 - 500 RWHP should feel like.   When all of this is put together, drivers find they have a whole new windshield experience!

Since both engine and transmission are controlled by the same PCM (Power Control Module), truck owners will need to match their engine and transmission tuning.  EFILive, HP Tuners and EZ Lynk custom tuning from Calibrated Power Solutions have the capability to tune the 68RFE and the 6.7L Cummins.  We have logged countless hours developing our calibration and would we happy to talk you about it.  If you would like to learn more about custom tuning click on the link below and fill out the corresponding form.  A Cummins performance specialist will contact you within 1 business day to answer all of your questions.