Looking the upgrade my suspension on 2005 jeep liberty

[u2slow]

I can't speak for the Dakota shocks (but I have about a 3" lift and need rear springs.. Got a part number of year/model to help me out?)

I'm using 97-02 4runner rear coils and Monroe Load Adjusting shocks #58649.

 

[mercdudecbr600]

2800ish in 6th.

does your rear driveshaft have a harmonic balancer? And what is your u joint operating angles?

 

[u2slow]

does your rear driveshaft have a harmonic balancer? And what is your u joint operating angles?

No balancer and I can't measure the angle for 2 weeks.

I do know most of the angle is at the fwd end - almost nothing on the rear. I've never been happy with the arrangement (visually) but it also hasn't given me any trouble.

 

[mercdudecbr600]

Interesting. I’d bet you’re at 7-9deg u joint operating angle, but please measure and get back to me. Recommended is 1-3deg. Outside of that range, driveline theory states you’ll get vibration and reduced u joint lifespan.

Hearing this I’m starting to wonder if my harmonic balancers extra weight is throwing off vibrations due to the highish operating angle.

 

[seafish]

I’m starting to wonder if my harmonic balancers extra weight is throwing off vibrations due to the highish operating angle.

At least on the Dodge Ram trucks from the same timeframe, those viscous harmonic dampeners on the DS are a known failure point that eventually cause vibration

 

[u2slow]

IIRC, the damper is a heavy ring on the yoke (not the shaft) and is situated on rubber (not viscous anything). The rubber usually ends up shrinking and ring comes loose.

I've lost track of which rear driveshaft is on the KJ (not home to check), but I do know the pinion angle is higher than I want. Still, not eating ujoints or causing any noticeable vibration.

 

[burntkat]

Interesting. I’d bet you’re at 7-9deg u joint operating angle, but please measure and get back to me. Recommended is 1-3deg. Outside of that range, driveline theory states you’ll get vibration and reduced u joint lifespan.

Hearing this I’m starting to wonder if my harmonic balancers extra weight is throwing off vibrations due to the highish operating angle.

You're talking about the weight on the snout of the pinion, not the balancer on the motor I assume? That's more accurately known as a tuned mass, if my info is correct. Just to avoid any communication... Can't imagine how a harmonic balancer on the crank would cause this.

 

[burntkat]

IIRC, the damper is a heavy ring on the yoke (not the shaft) and is situated on rubber (not viscous anything). The rubber usually ends up shrinking and ring comes loose.

I've lost track of which rear driveshaft is on the KJ (not home to check), but I do know the pinion angle is higher than I want. Still, not eating ujoints or causing any noticeable vibration.

That would definitely be a balancer. My Jeep has a mass that bolts to the side of the snout of the pinion part of the diff casting... If that makes sense....

 

[u2slow]

My Jeep has a mass that bolts to the side of the snout of the pinion part of the diff casting...

I have definitely removed that one.

 

[seafish]

is situated on rubber (not viscous anything). The rubber usually ends up shrinking and ring comes loose.

you are correct…meant to say "elastomeric"

 

[mercdudecbr600]

You're talking about the weight on the snout of the pinion, not the balancer on the motor I assume? That's more accurately known as a tuned mass, if my info is correct. Just to avoid any communication... Can't imagine how a harmonic balancer on the crank would cause this.

No, I mean a driveshaft harmonic balancer. At least on the 45rfe trans, the slip yoke side has a friction fitted balancer/mass.

It looks and probably functions very similar to a motor hb.

 

[mercdudecbr600]

At least on the Dodge Ram trucks from the same timeframe, those viscous harmonic dampeners on the DS are a known failure point that eventually cause vibration

I suppose that’s why they were eliminated in the later models and you won’t find them on aftermarket drivelines.

According to driveline shop, they are great at soaking up small imperfections but amplify larger ones (like high operating angles, I’m guessing). Another interesting issue is that the OD dia of the ds is unique and the (large) ds shop I went to didn’t have a “fixture” to bolt up the slip yoke so they made due with a lathe mount to balance.

Anyways, this stuff is driving me nuts!