The 3.7 liter is, for the most part, the 4.7 V-8 with two fewer cylinders. It was designed to take over the 2.5 liter four-cylinder, as well as the 3.9 liter V6 engine, both used only on Jeeps and trucks. The first time it was used was for the optional engine on the Jeep Liberty, followed shorter after as the 2002 Dodge Ram's base engine. In both instances, the 3.7 V6 was manufactured intendenly as a five-speed manual transmission or an automatic. In the future, it was attached to a six-speed manual.