Because half of them are two cylinders shorter than the other half
. Seriously, the 4 bangers have a longer rear driveshaft. The AX-5 is a slightly shorter transmission, and the 4 banger is of course two cylinders shorter than the 4.0 Not to say that it's like 6 inches longer, it's about an inch or inch and a half if I remember correctly.
That's exactly right. If you hear of someone running 4-4.5" of lift and no SYE it's a 4 banger and a 5 speed. a 4 cyl with a longer automatic transmission is more likely to have problems too.
Don't take this to lead you to believe that if you have a 2.5/5 sp combo that you definately won't need a SYE... it can go either way, and when offroading in really off-camber stuff that driveshaft is under alot of stress with that much lift and the stock TC slip-yoke style output.
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Megamole - most of the kits will have longer swaybar links, with the disconnects optional. That's all you need, but the disco's make a huge difference when offroad.
Most any kit over 3" should have a dropped pitman arm included. If it doesn't then buy one... you'll need it to correct the steering angles.
As for longer shackles, you don't need them unless both ends of the springs are military wrapped eyes like BDS.
What happens there is the rear military wrapped eyes hit the rear crossmember when the springs are fully compressed, making a klunking sound. It's really harmless but annoying... I ran mine like that for several months before I got 1" longer than stock shackles. You do have an alternative, which I would do instead of the longer shackles... you can cut the top half of the military wrap off with a cutting wheel so they look like the "half military wraps" you'll see on some springs. The front is fine with the full military wraps. If you leave the rear trackbar on it probably won't even happen at all, but most people remove it when they lift YJ's as it adds a little rear wheel travel.
The only person I have ever known to run Black Diamond leaf springs was on here. I honestly can't even remember who it was I like the spring design (flat seats like Old Man Emu springs), but I really don't know anything about them other than that.
