Check this out :
http://www.jeeps-offroad.com/showthread.php?t=4740
I don't think the AX15 is worthwhile for a 4 cyl. It maybe stronger, but the gearing is just about the same. You might as well get stonger AND geared low.
Ryan, don't do the V8 swap!!! Everybody and their uncle does it. Save your .030 over for a drag car! My 7.05:1 1st gear is louder than my engine. People always ask,"what the h3ll is in that thing?" It's different and cool! BUT, if you really wanted a Chevy V8, with the SM420, all you need is a bellhousing and clutch component change.
...Ryan...SM420...swap...:subliminal message:
From Bill in Utah:
"I'd say getting 16-18 mpg highway out of a 4 cyl is inefficient to say the least."
Hey, Wild Bill, It may look bad, but trail Jeeps like mine and Ryan's weigh around 4K lbs, which is probably twice as much as your corolla. They're also about as aerodynamic as a brick and have a lot of parasitic loss from bigger trannies and t-cases to spin. Makes you wonder why they put a 4popper in to begin with.
Oh well, at least it adds character and has good torque for the trail.
I sat in a Commander at the Great American Jeep Rally (up here in New England) back in Sept. It was cool and reminded me of a big XJ. I like the 4.7LV8 too instead of the HEMI. Too many cylinder deactivation gizmos for me. My wife would probably get more tickets too.
I kinda like the Liberty. I think the IFS stinks, but again, soccer Mom's are taking over! The 2.8L CRD isn't available here in Mass yet due to emissions. Soon, I hope.
Anyway, now I'm starting to ramble and will stop before I go on for hours. Build it, wheel it, fix it. That's it!
Happy Trails.