In 2007, Chrysler debuted the new 6.7 Powerplant in the all new Dodge Ram, and Dodge wanted a transmission that was specifically designed for function. The previous platform utilized the Torqueflite 48RE platform and had been around since the late 50's when they released the first 727 in 1956 after purchasing the license from Simpson on the gearset in 1955.
The 46/47/48 Chrysler platforms were 3 and 4-speed units that were mechanically and hydraulically controlled, with the most notable control system being governor pressure.
The first improvement Chrysler wanted to make over the Torqueflite platform was, obviously, the amount of forward gear. For the 68RFE transmission, Chrysler opted to change to a six-speed unit. The additional gears allowed Chrysler to add higher 1st-gear ratios and tighter shift recovery from one gear to the next. The tighter shift recovery essentially keeps the vehicle in higher averaged horsepower and torque numbers, while also adding torque multiplication.
The gear ratios were increased. as well. The new 68RFE boasts a whopping 3.23:1 first gear, compared to the 2.45:1 first gear found in the previous 47/48RE platform. Chrysler also increased second gear to a 1.83:1 versus the 1.45:1 found previously. The 68RFE was also given two overdrive gears, with 5th being .81:1 and 6th with the very deep .62:1. The predecessor had a single overdrive that was a .69:1.
The Category Kits
The SunCoast Category 68RFE transmission rebuild kits are designed and developed with intentions of taking a systematic approach to solving the issues with the 68RFE transmission. We approach each deficiency and need from a scientific approach.
These kits offer you the same recipes that are used in our facility. We aim to offer you the most complete series of 68RFE rebuild kits available on the market today.
The Smart Tech Drum
The factory overdrive clutches are at a high risk of failure when towing or installing aftermarket programmers, delete kits, or larger turbos. This is in large part to the fragile and thin (.034) single-sided clutches. When exposed to increased torque or higher temperatures, they will distort, causing additional clearance and uneven apply. This will always result in burnt clutches. These clutches in the overdrive housing are, by far, the weakest link in the 68RFE transmission design.
The Sonnax Smart Tech 68RFE overdrive drum addresses these issues. The new billet clutch housing holds a physically taller clutch pack, allowing the overdrive apply clutch area to increase 16%. In addition to the increased apply surface area, the thicker clutches and steels increase clutch steel mass by 28%, drastically improving the heat dissipation.
The new 68RFE overdrive clutch drum also comes with a top bolt-on plate to help eliminate clutch pack flexing and distortion that contribute to premature failure.
The 2C Piston
The factory molded piston is prone to uneven apply which leads to excessive heat in the clutches and steels creating premature failure. In this 68RFE transmission rebuild kit we replace the factory piston with a much improved billet piece that also allows for one additional clutch further increasing surface apply area. This new billet apply pistons corrects these issues and adds matched performance.
The Solenoid Repair and Spacer Kit
The factory 68RFE transmission is known for giving false pressure switch codes. These false 68rfe pressure codes some times are the result of circuit board flexing. The 68RFE transmission solenoid block can very easily be rebuilt with this Sonnax kit. This 68RFE transmission solenoid repair kit uses both a spacer to stop the circuit board flexing and improved sealing components to prevent leakage.
There factory 68RFE transmission accumulator plate is very weak and not held securely. This problem becomes even more apparent with the addition to higher line pressure which is a very common modification performed on the 68RFE
The Torque Converter
This Category 1 SunCoast Torque Converter fits 68RFE transmissions and is engineered to handle all of your every-day duties. Whether you’re towing a camper or hauling dirt to a job site, this torque converter is designed to improved vehicle response and give you years of solid, reliable performance. It comes with furnace-brazed fins and hardened turbine splines. The clutches in this converter are carbon-graphitic for precise and accurate lock-up.
If you’re looking to increase the performance of the factory unit—and looking for a cost-effective solution—this is the converter for you. This converter, while great for heavy duty towing and hauling, is it not intended for racing.
This torque converter has a 2,000 RPM factory stall speed.
The Flex Plate
The Sun Coast 68RFE-BFP Billet Flex Plate for your 2007.5 - 2018 Dodge 6.7L Cummins is a must have when it comes to putting power to the ground in your truck. The high torque of your Cummins in conjunction with a better designed torque converter can transfer the torque with no slip. The flex plate is bolted to the crank shaft, then the converter is bolted to flex plate. The torque from your Cummins is transferred to the flex plate, from the flex plate to the torque converter then to your input shaft in the trans. With increased torque from the engine and no slip out of the converter it can crack and/or rip the center out of a stock flex plate.
The Sun Coast billet flex plates are CNC machined from a forging for strength and reliefs are machined out between the converter mounting area and the crank flange to enable some flex. We designed our flexible billet flywheel with the understanding that it needs to flex but at the same time we added extra thickness to prevent cracking. We started with a better quality material and a better manufacturing process to make it stronger. Our flexible flywheel made or exceeded all the SFI specification 29.3 requirements for materials, mechanical properties, design and rotational integrity.
A SFI certified flywheel flex plate is required on drag racing vehicles running 11.99 and quicker in the 1/4 mile and 7.49 and quicker in the 1/8 mile, or any vehicle exceeding 135mph. It was changed in 2008 from the 29.1 SFI specification to the SFI specification 29.3 for automatic transmission flex plates for diesel applications.
The new rules for the flexplate requires that the material can not be a stamped metal as many OEM and aftermarket flex plates are. To maintain the SFI specification 29.3 requirements, the flex plate must be replaced every three years.
The Input Shaft
Probably the first hard part to fail on the 68RFE is the input shaft. When you add larger wheels and tires and a few minor upgrades this problem becomes even more likely to develop.This input shaft is a drop-in replacement part for high power/torque applications. Made from billet 300 Maraging (VASCOMAX) steel alloy for high yield strength. The shaft is also heat treated and precision ground. The shaft then is gun drilled through hole to eliminate stress risers often associated with conventional drilling procedures.
These new 68RFE transmission rebuild kits are designed with the builder in mind, we offer from mild to wild depending on what your needs are.