42RLE Automatic Transmission - 2003-2006 Jeep 4.0L 4-Wheel Drive Transmission Only. The ATS 42RLE is engineered to hold the power and abuse Jeep owners can throw at it. Substantial increases in clutch pack surface area, line pressure and shift quality provide the reliability Jeep owners demand.
42-RLE Transmission:
The 42-RLE transmission that is used in the 2003 to 2012 Jeep was never designed to handle the abuse of after market add-ons such as over sized tires, extreme off-roading, increased power levels, higher gear ratios or towing. The small 42-RLE factory transmission also has a very low volume cooling system, the low cooler flow does not allow adequate transmission fluid circulation through the torque converter in order to properly cool the torque converter during normal driving much less stressful situations such as four wheeling or hauling any additional weight over stock.
The primary hydraulic pump of the transmission is not big enough to support the increased pressures and lubrication that is needed to keep the clutch packs and gear sets alive at higher power levels.
Other design limitations of the 42-RLE plague the ability of the transmission to handle much power over stock. The stock torque converter is manufactured using stamped steel parts that make up the lock-up porting of the converter. The converter cover will deflect under power causing the converter clutch to slip under load creating excessive heat and clutch material to shed from the lock-up piston. The combination of heat and debris from the converter clutch causes transmission failure as the material from the torque converter is flushed into the transmission.
The ATS modified 42-RLE has been redesigned to correct all of these problems and handle increased power levels of larger displacement engines, Super charged or Turbo charged engines, Larger tires or heavy towing. We understand the real world abuse that this transmission is asked to do in modified applications so we came up with the fixes for it. ATS has developed a combined technology utilizing recalibration of the hydraulic circuits inside the transmission, including revamped accumulator rates, reprogramed clutch to clutch apply and release timings, and line pressure rise rate to perfectly match the torque output of the engine.
These enhancements, along with other key hydraulic modifications which ATS makes, must be done to ensure the clutch packs have the correct apply and release rates when commanded on or off. As well, the transmission hard parts have many limiting weaknesses which do not allow for increased power levels over stock. Specifically, the light duty shafts and hubs must be addressed. All of these areas are addressed in our transmission to allow for increased power levels and reliability. Here are some of the modifications we do to the 42-RLE transmission so it will handle the extreme use that your looking for.
Inside the Transmission:
Pump Assembly:
The pump body is redesigned to utilize an over sized pump gear set, this provides for increased cooling and lubrication to the torque converter and transmission gear set. This redesign also eliminates the common pump problems that causes premature transmission failure due to excessive heat. The main pressure regulator circuit is modified to enable a broader range of pressure that can be commanded from the TCM.
This allows the pump to lower line pressure when the engine is at low loads and more responsively raise pressure above stock to react with increased engine torque and horse power levels.
Rotating Clutch Drum Assembly and Clutch Packs:
Clutch modifications are generally one of the most impactive and important items that can be upgraded in any transmission. In the case of the 42-RLE transmission, there is little room for additional clutches so modifications must be done to pressure plates providing increased clutch surfaces. All clutch packs are replaced with High performance clutch plates and steel separator plates providing the best friction surfaces available. The problematic Over Drive clutch pack has an increased clutch count maximizing its ability to hold torque.
Valve body:
The valve body is considered the nervous system of the transmission; the valve body is responsible for converting the electrical signals from the TCM into hydraulic actions. The 42-RLE uses a non-synchronous, clutch-to-clutch design. This means that the shifts from gear to gear must be timed perfectly thereby releasing and applying a friction clutch to achieve a flawless shift.
Because of the sensitivity of the hydraulic circuits, we heavily modify many areas of the valve body. Hydraulic oil flow is ported to certain clutch packs where additional pressure is needed. The accumulator piston seals have been redesigned to ensure hydraulic pressure integrity. The accumulator plate is made of high-grade material to compensate for the additional pressure that the accumulator pistons and springs exert during heavy power situations. Also, the ATS 42-RLE valve body can be purchased separately and installed in a stock transmission for increased transmission capacity.
Planetary gear set:
The main planetary gear set is reinforced to prevent the pinion deflection that causes gear set failure.
Case and Pan: (Pan is sold separately)
The main transmission case does not require a lot of conditioning aside from a few small hydraulic modifications to allow for proper oil flow. At higher power levels the transmission case does need to be strengthened. This is a simple fix that is taken care of with the optional heavy-duty cast aluminum transmission pan, which was designed in part to act as a girdle, thus eliminating the flex in the case.
The heavy duty aluminum pan will clear aftermarket skid plates and the cooling fins allow the transmission to run cooler and it has an over sized drain plug on the side so it can be accessed for easy service.
Application:
- 2003-2006 JK/JKU/TJ
- Jeep HEMI
- Gas
- 4WD
