Rear vibration when braking under load

[Fastpitcherus]

Hello all:

When under load with my trailer, I get a rear-end vibration when hard braking. Doesn't happen when not under load.

No play in the driveshaft at the rear u-joint. But I just noticed there is a fluid leak on the u-joint side of the rear differential.

Any ideas?

 

[tommudd]

So you have a pinion seal leaking
Vibes?? Check the Upper and lower rear control arms
Doesn't do it without the trailer ??
Do you have ABS?
What year ?
How many miles ?

 

[Fastpitcherus]

Lower control arms were recall replacement not too long ago. Haven't checked the upper arms - what should I look for there?

2007 Lib with about 76K on it.

Not sure if it has ABS - I'm assuming. I bought it used a year ago.

 

[yellocoyote]

Never good to assume. It was an option in earlier model years, and standard in later years (IIRC).

What about those other things that Mudd asked you?

 

[Fastpitcherus]

Only does it with the trailer attached.

 

[Fastpitcherus]

More information. Rather than calling this a vibration, I'll call it a "groaning" noise. It seems to be coming from center, directly below the rear seats.

Now I'm thinking it is the upper rear arm control ball joint. Would that make sense?

Also, could bad UR arm ball joint have caused the pinion seal to start leaking on the rear differential?

 

[tommudd]

check the rear upper control arm ball joint, they wear out.Also no it would not cause the pinion seal to leak, another wear item

 

[HoosierJeeper]

07 would have ABS for sure as well.

 

[Fastpitcherus]

Thanks all - appreciate the input.

Is the ball joint easy to replace? Also, if I change the ball joint, should I also change the bushings?

 

[Porkchop]

Have to change the complete upper control arm as one unit not to hard to do.

 

[Snail Farmer]

Have to change the complete upper control arm as one unit not to hard to do.

Technically you don't "have to" replace the whole arm, but it's highly recommended. I tried replacing just the bushings and ball joints when mine went bad, but it didn't even last 4 months before they were shot again. Get the whole arm assembly, and make sure it's OEM, not aftermarket.

 

[Fastpitcherus]

Thanks everyone. Quite a difference price wise between OEM and others. Yikes!

Does the project require support of the differential with a jack during replacement? I've seen differing write-ups about that.

 

[tjkj2002]

Thanks everyone. Quite a difference price wise between OEM and others. Yikes!

Does the project require support of the differential with a jack during replacement? I've seen differing write-ups about that.

There is a huge difference in quality also which makes that price difference seem like nothing.Those aftermarket version may last a year and your doing it again and again.

You support the KJ's weight on jack stand to take the weight off the rear axle(place jack stands at rear lift points).Does not need to be so high as the rear wheels are off the ground but enough where you can manipulate the axle to align everything.

 

[Fastpitcherus]

Thanks TJKJ! And everyone else.

I'm like one of your (the "collective" your) kids. I only write home when I need help or money.

Awesome site - never quit!!