1999-2018 Cummins TransGo Performance Reprogramming Shift Kit (45RFE-HD2)

TransGo Performance Shift Kit (45RFE-HD2)

1999 to 2018 Chrysler, Dodge, RAM and Jeep vehicles equipped with the 45RFE, 545RFE, 65RFE, 66RFE and 68RFE can develop excessive wear at the torque converter clutch (TCC) accumulator piston bore in the pump.

In order to control the converter clutch apply rate, the computer varies the pulse width modulation of the LR/CC solenoid. In doing so, the solenoid output acts on the TCC accumulator piston and the TCC regulator valve simultaneously. The purpose of the accumulator piston is to dampen the constant oscillation from the LR/CC solenoid and to influence the initial regulation rate of the converter clutch regulator valve.

When the TCC accumulator bore wears out, the LR/CC solenoid output can leak across the accumulator piston and onto its spring side, which is vented to the sump. Consequently, with the bore wear the TCC regulator valve will lose some of the LR/CC solenoid signal oil which will have an in-direct effect on the regulation of the converter clutch slippage. As a result, the lock-up clutch can slip, shudder, or even not apply at all. If the slip is severe enough and given enough time, the computer will then set a lock-up performance code.

These vehicles will also let the converter clutch slip speed ramp up slightly in between gear changes to make sure the shifts are smooth. When the TCC piston bore is worn the desired slip speed can go over the specified RPM amount during a gear change. With the resulting gain in engine RPM, it produces the sensation of a flare during the gear change.