48RE Shift Kit 2003-08, new and ready to install. Fits the 48RE. Ships fast from the USA.
This is the entry-level TransGo kit for the 48RE, the four-speed behind the 5.9L Cummins and the 8.0L V10 in 2003-2008 Ram 2500 and 3500 trucks. Buyers usually land here after a rebuild quote, or after a truck that tows starts sliding through the 2-3 shift, lets the converter clutch slip on a grade, or sits in Park overnight and takes a second to grab Drive. TransGo's own instruction sheet sums up the kit as more torque capacity, firmer lockup and shifts, and less drainback, and it is the kit TransGo calls perfect for diesel trucks.
The 48RE decides when to shift with an electronic governor pressure solenoid and transducer, but how hard each band and clutch applies is still set by valve body hydraulics: the pressure regulator, the throttle valve, the boost valve that raises line pressure in 4th and lockup, and the check balls and accumulators that cushion each apply. TransGo works on those circuits. The kit adds a shim and spring seat with new inner and outer pressure regulator springs, a new plain lower 1-2 accumulator spring, a new manual valve that keeps oil in the converter while the truck sits in Park, a new lockup bracket, a limit bushing with ball and spring, a transfer plate for the part throttle body, and a Cherrybomb check ball. A few small drilling and filing steps finish the recalibration. For trucks with the throttle motor and a power chip or programmer, a gold spacer is supplied to stop a light-throttle 2-3-2-3 shuttle.
A shift kit will not fix a failing governor pressure transducer, a bad throttle valve actuator or a worn pump. If the truck starts in third and stays there, or sets governor or TTVA codes, sort that out first using our 48RE Ram 2500 Cummins shift problems guide.
Put a gauge on the line pressure tap and road test the truck loaded. Sonnax notes that a healthy 48RE should show roughly 22-28 psi of line rise when it goes into 4th or the converter applies; a stock body that is merely soft will show normal numbers that are just low for the load you are pulling, while a body that loses pressure or will not rise points at bore wear. Our harsh or delayed shifts walkthrough runs the tests in order.
The listing covers the 48RE from 2003 through 2008, which spans both throttle systems: early trucks with a TV cable and 2005-and-later diesel trucks with the electronic throttle valve actuator. TransGo gives two checks before you start. The 8th digit of the VIN should be C for a 48RE (a 6 means a 47RE), and the main valve body plate must have the balance hole TransGo shows in its instructions; if yours does not, TransGo directs you to its TFOD-Diesel kit instead. The kit is not compatible with a 46RE or 47RE valve body swapped into a 48RE or with a body already modified by someone else. If you are unsure, send us your year and VIN. A complete 48RE valve body for 2003-2008 and the heavier TransGo 48RE-HD2 reprogramming kit are alternatives, and every option is on the 48RE parts page.
| Fits | 48RE 2003-08 |
| Part type | Shift Kit |
| Condition | New |
| Brand | TransGo |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes, the listing covers 2003-2008 48RE units, which includes the 2005-and-later diesel trucks with the electronic throttle valve actuator. Confirm the 8th VIN digit is C and that your main valve body plate has the balance hole shown in the instructions.
No. The kit replaces regulator springs, the manual valve, plates and check balls and calls for small drilling and filing steps, so the valve body has to come out and be worked on at the bench.
No. Starting in third with no upshift is a failsafe, usually triggered by a governor pressure sensor, governor solenoid or TTVA fault. Diagnose and repair that first, then add the kit if the shifts are still soft.
ATF+4, the fluid Chrysler specifies for the 48RE. Check the level hot with the engine idling and the selector in Neutral.
This is TransGo's standard 48RE shift kit. The HD2 is TransGo's heavier reprogramming kit with more parts aimed at higher line rise and more direct clutch and band release oil for hard towing or added power. Both fit 2003-2008 48RE valve bodies.
