Hi, Ive been looking at how DC designed the rear suspension.

What Im tring to figure out is what keeps the axle from moving around under stress and torque. Partiularly Up and forward.

There are only 3 mounting points, 1 on top the diff with a single ball joint, and 2 control arms.
All of these are connected with flexable rubber bushings.

I had a couple of guys rock the KJ back and forth while I was laying under it and watching the rear suspention. There is a lot of movement in those lower control arm bushings and some movement in the upper boomerrang bushings.

What I think this all means, well

While a 3 link connection may had perfect geometry on paper, real life offroad conditions combined with rubber bushings, The KJ ends up with a loose sloppy rear wheel control.

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could this have anything to do with the vibration dampner (i think thats what it is) hangning off the diff?

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2006 Renegade 4x4

Well, sports car suspension it aint. And true, if you head into a turn with a modest amount of speed and use some hard braking, you will indeed experience some rear wheel chatter (right before you are looking at the world through a sideways windshield!). That all being said, the rear tri-link setup works admirably on the Liberty for what it is intended. Remember, manufacturers have been using rubber bushings with the same or far less tolerance for deflection on "linked" rear suspensions for literally decades with tremendous all around success. DC had to figure out how to keep wheels on the ground when off road with the relatively unforgiving IFS and a supple tri-link was their answer. If your desire is to get a much more "car" like feel from your libby, you can replace the bushings in the lower control arms with poly-urethanes that are sold for the XJ control arms. I am not sure there is an option for the front of the wishbone though.... A change of shocks will be in order as well.

-Adam

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My Libby SFA Project

How do the donkey nuts have anything to do with what hes talking about? They do cut down on vibrations from the driveshaft. Which is also a very stupid way of doing it.

The rear suspension also makes for some awsome wheel hop if you have a locker and spin both those back tires.

The rear axle will move under stress and torque. Was that the question? Im kinda confused about what you mean by "up and forward?" It will move up, but not forward. The control arms and the upper a-arm keep it from moving back and forth.

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If you are concerned about the rubber being too soft dont be we have guys running LT1's through locked axles with 5.13 gears and 36" iroks and they dont have any issues with rubber (very modified TJ's and YJ,s)

They use rubber cause it last way longer than poly it is quieter and cheeper I had LCA's on my TJ with poly joints and they sucked i got maby 8k out of them and they were shot
If you are thinking that a hiem or a all steel "ball joint" would flex better and also "give" less then you are correct they are less forgiving and flex better than rubber but they cost more you will have to fab whole new upper link deal and after you get all that worked out it will ride like c#$%
every bump that wants to push the axle back will just go right into the entire KJ rember that the KJ is a unibody so no frame to take the beating and body bushings to help smoth things out
You could go with a 1/2 and 1/2 type of set up with rubber on one end and a hiem on the other but the cost to benifit is just not there IMO

I have seen this same style suspension on a popular OTR bus. It's done for improved axle articulation. Yes, it can be sloppy at times and tends to throw vibration to the frame. Watch the center bushing on the upper link for wear. If it's like the bus suspension, the upper link won't last very long and you will get wheel hop & hammering when worn.

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2005 Liberty Sport CRD, Lt Khaki, sunroof

Thankful to now be an EX-CRD owner.