HELP!!!Rear end sway at Highway Speeds

[1800AskMatt]

Does anyone have issues running 70-75 mph on the interstate and have rear end sway like a crosswind or passing a big truck?


I have checked the sway-bar and end links, shocks, ALL 4point connections to the rear end housing and tire pressure.

Only thing that keeps coming to mind that I have done to the truck lately is 1.5" wheel spacers.

I check the torque again and it is right on the money.

I even removed them and ran a few days without them and have the same problem.

Any help or suggestions will be appreciated.



:bash:

 

[p nut]

Have you had an alignment done? Maybe uneven tire wear?

 

[Matthew Starr]

Does anyone have issues running 70-75 mph on the interstate and have rear end sway like a crosswind or passing a big truck?


I have checked the sway-bar and end links, shocks, ALL 4point connections to the rear end housing and tire pressure.

Only thing that keeps coming to mind that I have done to the truck lately is 1.5" wheel spacers.

I check the torque again and it is right on the money.

I even removed them and ran a few days without them and have the same problem.

Any help or suggestions will be appreciated.



:bash:

haha i love your screen name. I had that problem and it ended up be my new tires. I dont know how long ago you replaced you tires and if you've done 70mph + with em until now, but that is my only suggestion. Excuse my lack of knowledge with tires but my old tires (goodyear silent armor) had a stronger side-wall for against moving horizantally but less against moving vertically. then i got goodyear wrangler td's and it was the opposite cause they're more of a towing and offroading tire. The other thing i just thought of is that those wheel spacers (in my oppinion you should return and get wheels with an off-set) could be defective and be out off balance.

 

[1800AskMatt]

Have you had an alignment done? Maybe uneven tire wear?

Tires are still in great shape and have the right pressure. This was not a problem one month ago with same tires. Michelens

 

[J-money$$$]

I experianced this once awhile ago, but I was going 107 mph. Which is pretty dumb on its own in the runner. The rear end started getting light and almost drifting. I figured it was from my cr**py dunlop tires. I know this dosent help much but I just remeber the rear end doing werid things

 

[410toy]

I had a similar problem on my 1998 4x4 pathfinder. It turns out that I destroyed my trailing arms. I had them replaced and problem went away. I know 4runners are different vehicle but something to look into. You might just need to replace the bushings.

 

[Ron Helmuth]

Sway bar twisted?

Could your rear sway bar be twisted or otherwise no longer stock?

just a guess....

 

[00Spork]

I would take a look at your panhard bar on the rear axle, I was getting wierd handling characteristics(i felt like wind was blowing me, even though there wasnt any) and my panhard bar had worked itself loose somehow. Just check to make sure it doesnt have any play in it, and if it does, put some washers between it and the mounting bracket.

 

[techno]

:iagree:
The panhard bar is what gives the rear axle lateral stability and strength.

 

[KellyJ]

I have had the exact same sensation when driving my car lately at around the same speeds. Is there a way to tighten it up yourself if it is in fact loose?

 

[1800AskMatt]

I would take a look at your panhard bar on the rear axle, I was getting wierd handling characteristics(i felt like wind was blowing me, even though there wasnt any) and my panhard bar had worked itself loose somehow. Just check to make sure it doesnt have any play in it, and if it does, put some washers between it and the mounting bracket.

I was under the truck and had someone shake and push the truck and dont see any movement at the sway bar end links, shocks, 4 link on rear end and pan hard rod.

Confusing :bash:

 

[Ron Helmuth]

anyone with a good visual to help us out?

maybe someone has a good photo of the back end suspension pieces they would care to share?

Personally I do not know what the panhard bar would look like nor the trailing arms discussed above...

Would shaking the vehicle exert enough force to exhibit the symptoms of high speed instability?

Bushings are involved in the panhard bar right? And the rear sway bar?


I am learning all about the front end suspension and steering and tie rod inners.....just enough to be dangerous of course. he heee

 

[1800AskMatt]

Re: anyone with a good visual to help us out?

maybe someone has a good photo of the back end suspension pieces they would care to share?

Personally I do not know what the panhard bar would look like nor the trailing arms discussed above...

 

[RunnerUp]

check your lower links, my bushings had worn out and caused highspeed instability. you gotta get in there and look though, potentially even remove them to check the bushings.

you can not just buy the bushings though, you have to buy whole new arms.

 

[1800AskMatt]

check your lower links, my bushings had worn out and caused highspeed instability. you gotta get in there and look though, potentially even remove them to check the bushings.

you can not just buy the bushings though, you have to buy whole new arms.

Really, buy new ones?


I got in there with a prybar and nothing really had any slack

 

[RunnerUp]

there wouldnt be any slack while your truck is on the ground. you will have to visually inspect them. how many miles do you have on your truck? is the rubber bushing appear dry rotted or have ANY holes in it at all? can you stick a safety pin needle into it easily?

 

[dzlpwrd]

i have the same issue with my wifes 01. toyota offers the bushings they were $37 each. i am looking for poly bushings for mine. if i can not find them i will have some made at my local machine shop. the orignal ones are just pressed in. the condition seemed to get more pronounced after i replaced the shocks.

 

[Atreyus]

I have the same problem omg especially on the freeway lol.

 

[TxAg4runner]

got the same problem with mine. Replaced the entire front end. Balljoints, tie rods, sway bar, etc. Rear end looks fine. New tires too. I've had 3 mechanics look at it. Can't figure out what the deal is. Only thing I haven't done is replace the shocks.

 

[mikeleach]

I have the exact same problem and it too got much worse when the shocks were replaced. Found a broken stabalizer bar link in the front and a bad ball joint at the same wheel. I replace them and it helped a little but still need 2 hands over 65. The rear end seems tight but am going to start taking bars off this weekend. It's almost like the rear end is doing the twist.