About My Tuning:

5.9 Cummins and 48RE Custom Tuning: Performance, Towing and Daily Driving

I’m sure you have heard or read: 48RE shift points can only be adjusted by replacing the valve body or installing a shift kit…  This is not true.

There are literally thousands of adjustable engine and transmission parameters in the 2003-2007 ECM software and only a handful of those parameters are included in off the shelf tuning programs used by most custom tuners.  My tunes take full advantage of these “hidden” parameters.

I assure you the ECM/TCM is in complete control of the shift points and torque converter lockup in a 48RE Transmission which you will notice immediately when you drive your truck the first time after installing my tunes.  Your truck will drive like it should have from the factory…


On the trans side, you have a few options to “fix” the drivability issues:

Allison Swap- This is the most expensive option coming in around $15,000-$20,000 for a complete kit and requires at least a day or two of install (+ labor costs if you aren’t doing the work yourself).

Manual Swap- Comes in at about $5,000 or more and still requires custom tuning to be done right.  Also requires a few days of install and most likely some parts fabrication.  PS- If you are set on a manual swap, awesome! I can tune it for you and put you on a true manual calibration that will get rid of your PRND21 display.

5-9 Diesel Custom tuning- Comes in under $1500 and most packages are quite a bit less; plus it fixes most, if not all of 48RE drivability issues.  This product can typically be installed and operating in a couple hours or less.  By far, this is the best bang for the buck.  Rearranging the shift points and lockup schedule; gets you as close to a 5 speed Allison experience as possible with a 48RE, which in my experience is pretty close.

My thoughts: I have personally explored all of these options and I do like them all; I’m not knocking the Allison or manual swaps one bit.  The limiting factor here is money, time and ability to do the work.  With this information in mind, you should be in a good position to decide which route is best for your situation.

A Totally Different Driving Experience:

My tunes are a complete package of mated engine and transmission tuning which will provide an unparalleled driving experience.  I provide custom tuning for 3rd gen Dodge Ram trucks with a 5.9 Cummins engine and a 48RE transmission for model years 2003*, 2004, 2004.5, 2005, 2006 and 2007.

*2003 Model Year Trucks do not have 48RE tuning available at this time.

5.9 Cummins Engine Tuning:

  • 2003, 2004, 2004.5, 2005, 2005.5, 2006, and 2007 Year Trucks
  • Increased Horse Power
  • Increased Torque
  • Increased efficiency

48RE Custom Tuning:

  • 2004-2007 Model Year Trucks
  • Raised 1-2 shift point
  • Lockup in Manual 2nd
  • Raised 2-3 shift point
  • Lockup in 3rd gear that holds while coasting
  • locked 3-4 upshift
  • Tow Haul Button converted to Overdrive Off.  (2006-2007 trucks retain tow haul and OD off functions at the button on the shift lever).

-Read how well it works straight from the source: My Customers

How The 48RE Works…

The 48RE is an electronic over hydraulic controlled transmission. The short story is, the electronics control the hydraulics and the hydraulics control the transmission. The long story: the ECM constantly monitors data from sensors located in the transmission and commands key hydraulic pressures which are determined by several electronic tables. Each of these tables get used under specific driving conditions. The ECM determined hydraulic pressures are what physically move the shift valves in the valve body back and forth resulting in upshifts and downshifts.

Hardware upgrades may help to some extent, but they can never fix the real underlying issue of poor factory programming.

By altering the data in the proper shift tables (not just the ones the tuning programs show), the 48RE shift points can be pinpointed based on electronic tuning alone with no valve body modifications.

Take me to the next article: What is the best tuner for a 5.9 Cummins?

Take me back to Custom Tuning Products


Have Questions?

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See my tuning in action…

High Altitude 12 Valve Tune Cold Start

An early version of my towing tune…