Vague suspension question (looking for guidance)

imactj2004

imactj2004

TJ Enthusiast
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SF Bay Area
Okay, first off, let me apologize up front that this question is so vague. Unfortunately, I know very little about this vehicle. I inherited from my father-n-law who had done all of the work himself and there is no paperwork to reference anything that he did. On top of that, I've never owned a Jeep (stock or modified) so I have no reference point of how things *should* perform. Having said that, I'm in love with this vehicle and am determined to get it restored to honor my wife's father.

This is an 04' Rubicon with a 2 inch lift. Not a full kit, but something cobbled together by my father-n-law. Appears to be based on ProComp ES3000 shocks and corresponding coils. I *think* that the control arms are stock but am not positive.

Here's the gist:
  • Rear end mystery: I can hear and feel a "clunk" whenever the weight shifts to the rear and/or releasing from that position. It happens in both of the following scenarios:
    • when hitting and then releasing the accelerator, the clunk is virtually synchronized to those actions. Notably, this ONLY happens when on flat ground. It does not happen when going up hill and gravity keeps all the wait in the rear or when going down hill with all the weight in the front.
    • when coasting in reverse on a slight and depressing and releasing the break, a similar thing happens: pressing on the break throws all the weights to the rear and cause the clunk. Releasing the break lets the pressure off.

Any ideas?
 
imactj2004 said:
sure, thing...can do. how much do you want to see? Just straight on, level? Or sub-picts of the control arms, sway bar, etc?
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A little bit of everything will allow others to let you know what you have as well as see anything that may be out of whack. I can say that pro comp isn't well liked here.
 
hosejockey61 said:
A little bit of everything will allow others to let you know what you have as well as see anything that may be out of whack. I can say that pro comp isn't well liked here.
Click to expand...
Cool, many thanks in advance. Here's the motherload. Pardon the surface rust...that's on my agenda too.
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Your upper control arms are stock, the lowers look aftermarket. I would suggest jacking it up and just checking for anything loose/ out of the ordinary. Spin the tires by hand to feel for any play in the driveline.
 
I have to say you did the BEST job of taking pictures! Most of the time people will post one or two pictures from about 6 feet in front of their Jeep and be done. Yours are awesome.

Check all of your control arm and shock bushings. Sometimes by moving the arms/shocks by hand is enough to see if they are completely shot. I bought my Jeep with the same shocks as yours and I could move the rears by hand and get them to clunk is how bad the bushings were. As far as suspension, it looks like pro comp to me. IIRC their springs weren't horrible but there shocks were some of the worst. Their control arms are garbage also. I see a dropped pitman arm without a dropped track bar bracket. The TJ's don't need a dropped pitman arm so I would return that to stock when you find time. You have aftermarket skids on the front lower control arm mounts. Not a fan of that style but to each their own. I also see a dropped skid plate. Lastly, I also see aftermarket swaybar disconnects but I don't know what brand.

Get under there and manhandle the items with bushings and then go from there.
 
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Good eyeball on the drop pitman!
For the OP, with an 04 it's fair to say a control arm bushing is past it's prime somewhere. The axle tries to throw the pinon up during power a vice versa when you let off. Control arms are supposed to hold that, but a bad bushing would let it get slap happy. I'd check it on the ground as well as in the air since things will change a bit. And unfortunately, there's a big list of other stuff for a Jeep clunk. Buddies was trashed control arm. Mine was transmission mount with the nuts almost all the way off. joy.
Cool rig. Very easy to fix a lot of stuff actually. You'll be fine!
 
imactj2004 said:
Okay, first off, let me apologize up front that this question is so vague. Unfortunately, I know very little about this vehicle. I inherited from my father-n-law who had done all of the work himself and there is no paperwork to reference anything that he did. On top of that, I've never owned a Jeep (stock or modified) so I have no reference point of how things *should* perform. Having said that, I'm in love with this vehicle and am determined to get it restored to honor my wife's father.

This is an 04' Rubicon with a 2 inch lift. Not a full kit, but something cobbled together by my father-n-law. Appears to be based on ProComp ES3000 shocks and corresponding coils. I *think* that the control arms are stock but am not positive.

Here's the gist:
  • Rear end mystery: I can hear and feel a "clunk" whenever the weight shifts to the rear and/or releasing from that position. It happens in both of the following scenarios:
    • when hitting and then releasing the accelerator, the clunk is virtually synchronized to those actions. Notably, this ONLY happens when on flat ground. It does not happen when going up hill and gravity keeps all the wait in the rear or when going down hill with all the weight in the front.
    • when coasting in reverse on a slight and depressing and releasing the break, a similar thing happens: pressing on the break throws all the weights to the rear and cause the clunk. Releasing the break lets the pressure off.

Any ideas?
Click to expand...
I had the exact same symptoms with my TJ, along with something similar up front, and it turned out to be shot control arm bushings.
 
hosejockey61 said:
I have to say you did the BEST job of taking pictures! Most of the time people will post one or two pictures from about 6 feet in front of their Jeep and be done. Yours are awesome.

Check all of your control arm and shock bushings. Sometimes by moving the arms/shocks by hand is enough to see if they are completely shot. I bought my Jeep with the same shocks as yours and I could move the rears by hand and get them to clunk is how bad the bushings were. As far as suspension, it looks like pro comp to me. IIRC their springs weren't horrible but there shocks were some of the worst. Their control arms are garbage also. I see a dropped pitman arm without a dropped track bar bracket. The TJ's don't need a dropped pitman arm so I would return that to stock when you find time. You have aftermarket skids on the front lower control arm mounts. Not a fan of that style but to each their own. I also see a dropped skid plate. Lastly, I also see aftermarket swaybar disconnects but I don't know what brand.

Get under there and manhandle the items with bushings and then go from there.
Click to expand...
Thanks for the notes. I had this jacked up and spent a good part of a full day checking every connection point but still no luck which is why I came here for any ideas. I'm starting to wonder if it's the rear sway bar bushings although I'm unsure if I would feel that in the cabin.

Talk to me about shocks. I don't have anything to compare too, and I'm currently chasing other problems, but shocks are on my agenda too. This ride is super super stiff for the road. I'm not gonna be rock crawling. This is going to be 90% daily driver with 10% basic trails, so I really just want to get everything stabilized and reliable. As of right now, I'm just starting from scratch with no context of what's been done.

For Pitman arm, how can you tell it's dropped pitman and/or what would a stock look like? I'm asking because I just looked at others online and cant' tell the difference. (And as a side note, there is a bit of play in the front, so my dad and I were were looking at the pitman arm and steering box over the weekend. was gonna save that topic for a different thread. :))
 
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imactj2004 said:
Thanks for the notes. I had this jacked up and spent a good part of a full day checking every connection point but still no luck which is why I came here for any ideas. I'm starting to wonder if it's the rear sway bar bushings although I'm unsure if I would feel that in the cabin.

Talk to me about shocks. I don't have anything to compare too, and I'm currently chasing other problems, but shocks are on my agenda too. This ride is super super stiff for the road. I'm not gonna be rock crawling. This is going to be 90% daily driver with 10% basic trails, so I really just want to get everything stabilized and reliable. As of right now, I'm just starting from scratch with no context of what's been done.

For Pitman arm, how can you tell it's dropped pitman and/or what would a stock look like? I'm asking because I just looked at others online and cant' tell the difference. (And as a side note, there is a bit of play in the front, so my dad and I were were looking at the pitman arm and steering box over the weekend. was gonna save that topic for a different thread. :))
Click to expand...
also, @hosejockey61 - for the sway links, because I don't know for sure what lift he had, but can tell that those links aren't correct and are hitting the body, I'm replacing those shortly with a new RockJock adjustable link kit. Overkill? Or good idea?
 
imactj2004 said:
Thanks for the notes. I had this jacked up and spent a good part of a full day checking every connection point but still no luck which is why I came here for any ideas. I'm starting to wonder if it's the rear sway bar bushings although I'm unsure if I would feel that in the cabin.

Talk to me about shocks. I don't have anything to compare too, and I'm currently chasing other problems, but shocks are on my agenda too. This ride is super super stiff for the road. I'm not gonna be rock crawling. This is going to be 90% daily driver with 10% basic trails, so I really just want to get everything stabilized and reliable. As of right now, I'm just starting from scratch with no context of what's been done.

For Pitman arm, how can you tell it's dropped pitman and/or what would a stock look like? I'm asking because I just looked at others online and cant' tell the difference. (And as a side note, there is a bit of play in the front, so my dad and I were were looking at the pitman arm and steering box over the weekend. was gonna save that topic for a different thread. :))
Click to expand...

DaveC said:
I had the exact same symptoms with my TJ, along with something similar up front, and it turned out to be shot control arm bushings.
Click to expand...
interesting...did you replace the bushings alone or full arms?
 
I noticed something similar, and found it to not be anything suspension related. This is a longshot, but figured I throw it out there.

Check your rear seat. If it's not latched in to the rear mounts really well it will clunk in those situations. I had mine with the back folded down, but still sitting flat. That unhooks the rear latches and it will bounce and clunk. Same result if the back is raised and the latch fails to catch.

Otherwise I would replace those stock control arms. I had various rattles and clunks in the rear of mine that went away when I started replacing suspension components.

And look at the upper shock mounts. Common place for issues.
 
I would check the driveshaft u-joints next. See if you see any rust around the caps which would indicate a dry joint.

It might also help you narrow it down if you get down next to the jeep while somebody else starts to drive forward. You might be able to hear where the clunk is coming from.

As far as shocks, it looks like the rancho 5000x are getting good reviews around here.
 
One of the easiest ways to check your lower control arm bushings is to have someone roll the Jeep forward and slam the brakes... While you look underneath from a safe distance to see if they move at the connections especially at the frame.

A coil spring TJ as well as most any other coil spring vehicle is four large springs that suspend the frame above the axles.

All the movement is controlled by rods and levers and the geometry of these and the condition of the bushings create what you feel driving by and large.

There are over 40 bushings underneath one ... If you will be diligent and thorough you might be surprised at at the results you can get.
 
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add on question for everyone here — how do I know what size lift is on my jeep if I didn't do the install? I think it's 2" but how can I confirm? Does it matter when I'm looking for add-on or replacement parts?
 
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