Kit Includes the Following
The 66RFE transmission is the big brother to the 45/545RFE transmission. The RFE platform was originally designed by Chrysler and was introduced in 1999 with the debut of the new Jeep Grand Cherokee. The "RFE" stands for Rear-wheel drive Fully Electronic control. The RFE design was mostly noted in the new design to have 3 planetary sets for a 4-speed transmission in the 45RFE.
The first improvement Chrysler wanted to make over the Torqueflite platform was, obviously, the amount of forward gears. For the 66RFE 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 66RFE 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 66RFE 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 with careful consideration.
These kits offer you the same recipes that are used in our facility when we build these units. We aim to offer you the most complete series of 68RFE rebuild kits available on the market today with proven combinations for a successful build.
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 66RFE 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 66RFE 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 66RFE 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
Zero Cavitation Filter Kit
The factory 66RFE has had many issues with pressure relief check valve system on the transmission pan filters. Initially Chrysler had issues with the plastic filter splitting in half. This was later remedied by adding a pressure relief valve on top of the filter. This later showed to be an issue as the valve would release itself from the filter all together.
This new bottom feeder filter kit allows the usage of a torqueflite filter. This filter conversion will not only prevent pump cavitation but will allow higher volume of fluid to be passed through the system. This will also improve fluid flow in high line pressure situations.
The system requires either a deep aluminum Mag-Hytec that we modify or a specific OE pan. This kit comes with a specific OE pan.
The High Pressure Tuneless Reprogramming Kit
TransGo High Pressure Tuneless™ Reprogramming Kits fit 2012 to 2020 Chrysler, Dodge, RAM, and Jeep vehicles equipped with 45RFE, 545RFE, 65RFE, 66RFE and 68RFE automatic transmissions equipped with gas or diesel engines. This kit provides increased transmission durability for engines with increased horsepower and torque output when aftermarket engine tuners and other modifications are installed.
Until now, when someone increased the power output of the engine, the only way to significantly increase the transmission operating pressure required reprogramming the computer. As a result, computer programming often leads to harsh or binding shifts, erratic operation and at times catastrophic internal hard parts failure.
Increasing main line pressure the conventional way with a pressure regulator spring could not be done because the computer monitoring system would recognize the higher than expected pressure and immediately set a code as well as putting the transmission into limp-in mode.
TransGo Tuneless technology provides a re-calibrated pressure curve that mirrors the throttle position and torque demand. Consequently, this elevated pressure curve delivers increased clutch and TCC holding capacity along with shorter cleaner shifts at all throttle openings. The patent-pending internally balanced calibrations provides a progressive clutch apply pressure that increases line pressure across the entire throttle span. As a result, max line pressure is now 210 psi which is a 30% increase over the OEM 160 psi max line! The Kit also addresses the converter clutch apply circuit with a built-in bypass to prevent converter ballooning that comes with elevated line pressure.
Features and Benefits:
The Piston Replacement
Accumulator piston scuffing and bore wear are common issues in Chrysler 45RFE, 545RFE, 65RFE, 66RFE and 68RFE valve bodies, especially when running increased pressures. The OE accumulator pistons have two seal rings. The seal groove at the open end of the piston is a larger diameter, with the seal ring acting as a guide to prevent piston-to-bore contact. The seal groove at the closed end of the piston is a smaller diameter and the seal ring acts as a conventional seal. However, due to the smaller seal groove diameter, the piston will contact the bore when side-loaded resulting in scuffing, wear and leakage of clutch apply pressure.
Sonnax accumulator piston kit 44894-01K features two guide seal rings, one at each end of the piston to prevent piston-to-bore scuffing when side loaded. Additionally, the oil sealing ring location is relocated on the piston allowing it to run in an un-worn portion of the bore enabling bores with moderate scuffing to be salvaged. Manufactured from 6061 billet aluminum, these pistons will upgrade late model applications with plastic pistons to prevent transmission failure due to piston breakage.
The Torque Converter
This Category 1 SunCoast Torque Converter fits 66RFE 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 are 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.
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