Why upgrade to an ATS 4R-Performance transmission package?
The advantages of the 4R-Performance transmission over any performance built 47-RE or 48-RE are many, here are a few of the advantages over the Dodge trans.
Shift quality is much better controlled by the 4R trans, all shifts are actuated by an on/off shift solenoid that passes clutch application through a clutch fill valve that also has an accumulator to better control clutch fill time allowing for precise clutch application. This provides a near perfect shift at all power levels. The gear ratios of the 4R-Performance Transmission are evenly spaced providing a consistent RPM drop between all shifts. This consistent RPM drop gives a smooth power transfer while reducing the air disturbance through the turbo charger maintaining even boost levels. The Torque converter clutch (TCC) application is a modern day type Pulse Width Modulation (PWM) signal that provides smooth controllable TCC application. All this combined, adds up to transmission that shifts through all the gears and applies the TC with smooth accurate operation.
ATS 4R-Performance Transmission advantage
Torque converter = The specialty built torque converter is custom manufactured to perfectly match the exact stall speed of the Cummins torque curve to provide the optimal RPM flash stall allowing the turbo charger to start making boost pressure while at the lowest RPM range possible. This is all because of the properly designed Turbine, Impeller and stator design. The billet stator directs fluid from the impeller back into the turbine to most efficiently harness the lost energy in the fluid that is not absorbed by the turbine. All this means the torque multiplication is maximized providing a very smooth power transfer and maximum torque transfer from the engine to the transmission at a RPM that is well with in the beginning of the torque curve of the engine. The lock up section of the converter is our patented Viskus Clutch pack design that allows for a smppnh transition from fluid coupling to a 100% mechanical engagement providing over 3000 foot pounds of torque transfer without slip! The overly built Viskus clutch pack allows for a pulsed in TCC application at any power level without the concern of damage to the clutch pack. What this means is the PWM application of the 4R-Performance trans can be utilized in the programing to slowly apply the TCC providing a soft application while not damaging the TCC. All this translates to even RPM drop any time the TCC clutch is applied. You will never again have to live with a hard TCC shift.
Gear Ratio = The 4R-Performance Transmission has a superb gear ratio set that really favors the Diesel engine. The gear ratio provides an even RPM drop between all shifts from 1st all that way to 4th gear. This coupled with the ability to release and apply the TCC between shifts gives the feeling of the smoothest power transfer at speeds up to 100 MPH! Here are the Ratios of the 4R-Performance Transmission, 1st=2.71:1 2nd=1.54:1 3rd=1.00:1 4th=0.71:1 R=2.88:1 The 47/8-RE transmission has a huge RPM drop when shifted into 4th gear, this presents a major problem when shifting into 4th gear because of the ratio change is so drastic generally causing a turbo charger boost pressure drop during the shift.
Full synchronous shift = The synchronous shift application of the transmission mean there are no ?clutch to clutch? timing concerns to deal with while making the transition between gear shifts. Most transmissions require a managed application rate to apply a clutch or a band while also having to manage the release of a clutch or a band to achieve a desired shift. All this over head presents a real problem when adapting to large power swings like a turbo charged diesel presents. This is the main reason the 47/8-RE transmission has a serious issue coping with the power fluctuation levels of the turbo charged Cummins. A 47/8-RE hydraulic structure does not support a way to control the release element pressure independently of the apply element pressure. The 4R transmission clutch application only requires a single feed to apply all four gear applications. The simplicity of the hydraulic circuits and the synchronous operation provide a perfect performance transmission platform.
The 4R-Performance Transmission has electronic line pressure control, electronic accumulator control and PWM TCC control = All this allows the precision turning capability so the user can not only control when each shift occurs and the converter clutch occurs but the shift quality can be altered by changing line pressure along with tailoring the accumulator rate to optimize shift quality throughout the entire power curve. Not only can we taylor the shift quality but we can also tie the clutch application, TCC apply and accumulator rate directly to engine load instead of only throttle percentage! This equated to the best shifting transmission you have ever driven!