The 42RLE is a 4-speed overdrive automatic transmission. The 42RLE comes in 2003.5+ Jeep Libertys. The 45RFE is a 4-speed overdrive automatic transmission, with an alternative 2nd gear ratio for downshifting. The 45RFE was replaced by the 42RLE in 2003.5+ Libertys. The 545RFE is a 5-speed overdrive automatic transmission. The 545RFE was the only transmission available in Liberty CRD models. The Liberty's maximum tow rating with an automatic transmission is Class III 5,000#. Mechanically, the 42RLE has 13 bolts and a straight crossmember, while the 45RFE and 545RFE have 15 bolts and a backwards angled crossmember. Electronically, vehicles equipped with the 42RLE have a 4 connector NGC PCM (Powertrain Control Module) with an integrated TCM (Transmission Control Module), while those equipped with the 45RFE have a 3 connector JTEC PCM and a separate TCM.
Gear Ratio Table
The NSG370 is a 6-speed overdrive manual transmission. The NSG370 comes in 2005+ Jeep Libertys. The NV3500 is a 5-speed overdrive manual transmission. The NV3500 was replaced by the NSG370 in 2005+ Libertys. The NV1500 is 5-speed overdrive manual transmission with an unsynchronized first gear. The Liberty's maximum tow rating with a manual transmission is Class II 3,500#. The clutch design of the manuals results in a lower tow rating than that of the automatics. A driver skilled in towing with manuals may be able to safely tow more than Class II.
Gear Ratio Table
Jeep Libertys with the 42RLE transmission have an auxiliary transmission cooler in front of the engine radiator. Libertys with the 45RFE transmission have a cooler built into the engine radiator. Liberty CRDs with the 545RFE have a combination transmission cooler & A/C condenser in front of the intercooler and engine radiator. Libertys with the NSG370, NV1500, and NV3500 manual transmissions don't have a cooler because manual transmissions lack a fluid pump.
Standard Coolers (3.7L Auto):
|Power Steering||Yes||No||Yes (Manual)|
An automatic transmission is more popular than a manual for off-roading. It removes the distraction, water leakage, and clutch wear associated with off-road manual shifting. These benefits come at a price, as an automatic is always heavier than an equivalent manual.