Another vibration question...

One Old Chief

One Old Chief

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Feb 13, 2017
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Location
Mesa, AZ, United States
I just bought my first TJ; 2001 Sahara with what looks like a 2.5 inch lift, new 32 inch Pathfinder AT's. I replaced the steering stabilizer with an OME and took it down to the garage for lube and alignment. Mechanic says the upper and lower ball joints are okay. The shocks look pretty good but I too have that vibration at 65 mph. Could it be the shocks? Rather than just start throwing money at it doing the remove and replace troubleshooting I would like to go at it methodically with the most common cause and work my way to the "I never thought it would be that" conclusion. Any thoughts, ideas or suggestions?
 
You say new AT's? Did you have put on or PO put on? Make sure they are balanced properly. The start with visually inspecting your track bar, upper and lower control arms and shock bushings. Make sure all connections are solid and that the bushings haven't dry rotted or worn out over time.
 
I had the tires put on. PO had the track bar replaced and the alignment guy said it's adjusting lock was loose. I'll check the bushings this weekend to see what shape they're in. Thanks for the advice! If I get down to replacing the ball joints is there one brand that stands out? I was looking at the Synergy brand; American made and sintered.
 
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The best way to check for slack in the front end is to get a look at it yourself. Have someone slowly turn the steering wheel back and forth and see if you can spot any slack. They can also rapidly turn it back and forth to see if some more violent forces expose the problem.
Look for movement at any joints starting at the pitman arm. Check TRE's, both ends of the trackbar, etc. Note that the drag link will rotate around it's long axis, and that's normal.
 
One Old Chief said:
I had the tires put on. PO had the track bar replaced and the alignment guy said it's adjusting lock was loose. I'll check the bushings this weekend to see what shape they're in. Thanks for the advice! If I get down to replacing the ball joints is there one brand that stands out? I was looking at the Synergy brand; American made and sintered.
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No to every aftermarket ball joint. Go with Spicer and only Spicer.
 
JP98 said:
You say new AT's? Did you have put on or PO put on? Make sure they are balanced properly. The start with visually inspecting your track bar, upper and lower control arms and shock bushings. Make sure all connections are solid and that the bushings haven't dry rotted or worn out over time.
Click to expand...

X2 to this advice BTW.
 
Thanks to all for the sage advice; lots to do this weekend. Very glad to get the word on Synergy before I spent the wife's grocery money. I'll let you all know what I find and try to get some pictures posted, too. Being technically challenged I'll have to get the grandkids to help with that part of it. A cursory look at the dust boots doesn't give me a warm fuzzy; they look like they might be OE.
 
One Old Chief said:
Chris... the tire shop did the spin balance.
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You have to keep an eye on the tire shops. Some of those guys are not very good at making sure the larger tires are dialed in just right. The don't allow enough time for the tech to spend on the larger tires getting it exact. This can cause them to be close enough for smaller tires but not so much for the larger tires and short wheel based light weight Jeeps.
 
One Old Chief said:
Chris... the tire shop did the spin balance.
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And what happened?

Be aware that speed sensitive shimmies/vibrations are generally always caused by some kind of a tire imbalance problem. And not many tire shops will take enough time to get big tires balanced well enough. I have had to return to my Discount Tire shop three times in one day before they finally took enough time to get them balanced so my speed sensitive shimmy went away. The bottom line to that is that just because the tires were balanced doesn't mean they're actually in good enough balance.

Shocks never cause speed sensitive shimmies, neither do ball ball joints. They can make it easier for out of balance tires to cause bigger vibrations/shimmies but they'll never be the actual root cause.

X3 to avoiding Synergy ball joints like the plague, they're very expensive junk that won't last as long as the OE Spicer ball joints the factory installed will. A very good upgraded Spicer joint is this one.... https://www.amazon.com/dp/B00UTD76GY/?tag=wranglerorg-20

Finally, a good steering damper (aka stabilizer) is a good idea but it'll never ever (!) cause any problems when it goes bad. It's never the cure for any problems either, its main job is just to isolate the steering system from bumps and jolts. When the front-end is in good condition, you could run without a steering damper and never notice it was missing. :)
 
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My Synergy Ball joints were shot in less than 6 months. After I saw them it was scary. Tops were fine bit the bottoms were totally about to come apart.

At first it was I blamed for not greasing, using 37 inch tires, yada, yada, yada.

I told them the factory joints were there for 10 years. These for less than 6 months. I also mentioned the power of the internet is strong. They replaced them and are on now. I had no clue and thought it was a fluke so sad thing is I have them on now. I'll wear them out and go Spicer next time. I will also take photos and work hard on ending or at least reducing their sales on them.
 
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Don't be afraid to take your tires back to the shop that "balanced" them to have them checked out. Also, don't be afraid to ask how the balanced them, how much weight their using, if they rotated the tire on the wheel to help them balance, etc. If you have a shimmy, they need to check their own work. A little shimmy now can turn into something worse later if you let it go, and then it won't be the shop's fault.
 
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PStov98TJ said:
Don't be afraid to take your tires back to the shop that "balanced" them to have them checked out. Also, don't be afraid to ask how the balanced them, how much weight their using, if they rotated the tire on the wheel to help them balance, etc. If you have a shimmy, they need to check their own work. A little shimmy now can turn into something worse later if you let it go, and then it won't be the shop's fault.
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What he said ^^^ Shops rarely take the time to balance to zero. Road force balancing may be an option too if you have a finicky tire.
 
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