I recently acquired a 2013 LC all stock. Anyone with this vehicle experience out of control rear end movement at highway speeds? Wondering if KDSS may be overcompensating. It's like the sway is being regulated by the system but the computer isn't keeping up and causing exaggerated side to side pulling back and forth. I might be overthinking this but the motion doesn't feel passive,it feels more reactive. If anyone could lend any advice it would be greatly appreciated.
Dangerous Rear End Sway @ Highway speeds
- Thread starter mrtraylor
- Start date
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Wow, that sounds bad. Have you checked that the KDSS valve is closed?
This PDF (step 3) describes opening the valve and has a picture of what you're looking for under the truck if you're unfamiliar:
http://www.sleeoffroad.com/technical/pdf_files/200_Series_KDSS.pdf
Others here will no doubt have better suggestions for you.
This PDF (step 3) describes opening the valve and has a picture of what you're looking for under the truck if you're unfamiliar:
http://www.sleeoffroad.com/technical/pdf_files/200_Series_KDSS.pdf
Others here will no doubt have better suggestions for you.
Is this when driving straight or turning (ie changing lanes). If it's while driving straight then I seriously doubt it's the KDSS. If it's while turning you'll feel increased body roll over base normal which I'm not sure I would describe as sway as much and the vehicle leaning to a side more than usual. Basically all KDSS does is one of two things:
A) Force both wheels on an axle to move up and down together when both left or both right wheels want to move together.
-An Example: When you are turning left at speed both of the right side wheels will want to move up in relation to the body due to body roll. KDSS will not let the hydraulic cylinder on the sway bars move forcing all wheels to have to move together due to the linking sway bars thus preventing body roll.
B) Allow diagonally opposite wheels to move together. Ie. Front right and rear left to move while the other two do not.
-An Example: You are driving over moguls and the front right tire is going up over a mogul. The KDSS will allow some movement of the hydraulic cylinders depending on the amount of movement delta between the pairs of diagonal wheels.
I would think it's more likely you have a bad shock that isn't properly rebounding than it being KDSS but I guess it's possible.
A) Force both wheels on an axle to move up and down together when both left or both right wheels want to move together.
-An Example: When you are turning left at speed both of the right side wheels will want to move up in relation to the body due to body roll. KDSS will not let the hydraulic cylinder on the sway bars move forcing all wheels to have to move together due to the linking sway bars thus preventing body roll.
B) Allow diagonally opposite wheels to move together. Ie. Front right and rear left to move while the other two do not.
-An Example: You are driving over moguls and the front right tire is going up over a mogul. The KDSS will allow some movement of the hydraulic cylinders depending on the amount of movement delta between the pairs of diagonal wheels.
I would think it's more likely you have a bad shock that isn't properly rebounding than it being KDSS but I guess it's possible.
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Also KDSS is a hydraulic system, there is no computer working it.
I have a 2013. I haven't noticed that at all. It does wander a bit on the highway, but it doesn't sway.
- Thread starter
- #8
Aired up to 35 psi prior so know it's not pressure. Wheels and lugs are secure. Only noticable in a straight direction. Only 36k mikes so doubting shocks are faulty unless you guys know something I don't about stock shock longevity. Was thinking I'd at least get 60-70k out of OEM's. I'll take a look at the KDSS valve and upload results. Thanks everyone for your input!
Check to make sure your tires (particularly rear) are ok...I have seen radials where the tread 'slipped' on tge carcass and gave this sort of behaviour. A tire/wheel or suspension problem in the rear will feel 'reactive' as you are countering/correcting its effect with the steering wheel. One of the reasons why it is easier to control a vehicle with a blow-out in the front rather than the rear.
Any update on this? If it were me I would seriously think about taking it to the stealership.
How many miles on the truck? Toyota has a 60month/ 60k mile powertrain warranty which would cover traction control and such.
If not for anything else, I wouldn't want to try and self repair only to have something go wrong and my insurance company try to pull some BS. I would be worried about liability.
How many miles on the truck? Toyota has a 60month/ 60k mile powertrain warranty which would cover traction control and such.
If not for anything else, I wouldn't want to try and self repair only to have something go wrong and my insurance company try to pull some BS. I would be worried about liability.
Any update? Also FWIW I've used a faulty pressure gauge and the 35 that I thought I was getting was more like 68, and that made for some seriously squirmy straight line driving. Worth a check...
I want to revive this thread. I have been experienceing swaying at highway speeds. I have BP-51s front and back. The trouble shooting I have done this far:
1) I went through the shocks to make sure the compression and rebound were matched side to side. I talk to ARB and they recommended upping the compression a notch. This didn’t help.
2) new tires 275/70-18 KO2s didn’t help
3) Fresh alignment at the same time as the new tires.
I think my next step will be to replace the rear shocks. Will a stock 200 shock still fit with OME 2722s? If so I may test with my old stocks.
It does seem more noticeable with a load in the back i.e. camping gear.
Any thoughts or suggestions are appriecated.
1) I went through the shocks to make sure the compression and rebound were matched side to side. I talk to ARB and they recommended upping the compression a notch. This didn’t help.
2) new tires 275/70-18 KO2s didn’t help
3) Fresh alignment at the same time as the new tires.
I think my next step will be to replace the rear shocks. Will a stock 200 shock still fit with OME 2722s? If so I may test with my old stocks.
It does seem more noticeable with a load in the back i.e. camping gear.
Any thoughts or suggestions are appriecated.
Taco2Cruiser
Crazy American Off Road
Yes, stock shocks and BP-51s (along with all other aftermarket shocks) are virtually the same compressed and extended lengths. So not one issue with testing your stock shocks.
SQRRRL
SILVER Star
How fast is high speed? I had my LC in stock form up To 100mph with moderate load and she felt just fine.
You should be running your LT275/70R18 KO2's at a Cold Tire Inflation Pressure of 41psi F/R. If you are running less than that, could be contributing to your problem.
HTH
Although I’ve not experienced handling issues with my stock LC, I know from other vehicles that alignment needs to be done correctly for proper handling. A fresh alignment doesn’t mean it’s been done right for your tire/shock setup. Did the shop know what they were doing?
Was the alignment done by a reputable shop? Do you have a printout?
The 200-series is not an unstable vehicle. Far from it.
Check for play in the suspension. Control arms. Steering rack, rack bushings. Both front and rear end.
The 200-series is not an unstable vehicle. Far from it.
Check for play in the suspension. Control arms. Steering rack, rack bushings. Both front and rear end.