Yep , I special ordered my 2015 Trail edition without it. Overcomplicated Street cruiser stuff just like the Lexus GX mall cruiser . you see no trail teams FJ cruisers with this heavy, outdated system with cylinders ,hoses and fluid transfer kdss system. Wait until the warranty runs out or bust one of them things up on the trail. Yuk
KDSS 2" Lean
- Thread starter dahorst
- Start date
Yep , I special ordered my 2015 Trail edition without it. Overcomplicated Street cruiser stuff just like the Lexus GX mall cruiser . you see no trail teams FJ cruisers with this heavy, outdated system with cylinders ,hoses and fluid transfer kdss system. Wait until the warranty runs out or bust one of them things up on the trail. Yuk
A form of KDSS was actually used in WRC- and Dakar-winning rally cars.
However, I can see how this system conflicts with the K.I.S.S. appeal of Toyota 4x4s (simple and durable).
Citroen Clinches Manufacturer's Title In World Rally Championship With Tenneco Automotive Kinetic Technology | Tenneco Inc.
Mitsubishi Wins Paris-Dakar with Tenneco Automotive Kinetic Technology
Also Note there is no KDSS option on Toyotas most capable 4Runner the TRD pro as It could not handle the severe off-road pounding. The system has a huge heat problem when cycled repeatedly , it's just not designed for off-road. it's really a cleaver way to have a bigger swaybar to help on the road handling and loosen it up off-road . it's very simple , very heavy but also very complicated in application and repair.
Only way I can see it overheating off road is if you're moving fast over very rough terrain. Typically off road you're moving slowly. I also don't hear of too many cases of damage..mostly people accidently draining the fluid. I'm interested where you are getting the heat problem information from?
Lexusbstrdchild
New member
"Slightly" more capable more like it. Slightly lifted, and more capable tires over the trail is about it. I think ditching the KDSS was more of a cost savings and warranty thing more than anything else. Much easier for the port to install the lift, and no cutting of the aluminum skid plate. I haven't heard of the heat issue either, can you cite anything?
sandcrawler
Senior Member
:loco:
simple yet complicated? yup. and it's the system that Toyota opted to use on their rubicon and baja 1000 runs
http://www.toyota-4runner.org/5th-gen-t4rs/76427-2010-baja-1000-ensenada-la-paz-4runner.html
heavy? My door jamb has a load carrying capacity reduction sticker of 5 Kg. Perhaps that is heavy but I know this driver could drop 5 Kg to compensate if needed.
The root of the problem of this 'lean' seems to stem from suspension work that went awry more than the KDSS itself being the culprit.
Hope OP finds the root problem and can fix it easily enough.
Eagle62
Member
Intruder
New member
I've done a little bit of off roading with mine including high speed runs down forestry roads and never experienced any sort of overheating problems. His are the type of posts I was talking about before.
I wonder if it's possible for any thread on this forum that mentions KDSS not to turn into a complete shit show.
Just bought a ball joint removal tool tonight so I can start the job. I want to avoid using a hammer like I usually do. Based on the instructions from overland warehouse, I only need to remove the sway bar bracket and the tierod to get out the strut. Should have an update tomorrow if the rain goes away.
nb rob
New member
great tool to have. The youtube guys that tap it out with a hammer live in the friggin desert.
Princess auto for the win
Honu*
New member
but on there truly legendary off road capable land cruiser there is KDSS 
and show me where Toyota said it could not handle it and that is why they did not put it on the pro ?
and please show me the documentation about the HUGE heat problem you say it has !!! and not a few folks on a forum who says it does !
and show me where Toyota said it could not handle it and that is why they did not put it on the pro ?
and please show me the documentation about the HUGE heat problem you say it has !!! and not a few folks on a forum who says it does !
I will explain the heat issue with KDSS. The system operates using hydraulic fluid transfer, pressure and valves. Very similar to a shock . the valves open and close to increase and decrease resistance. When the KDSS system is cycled repeatedly quickly like running through the desert the fluid heats up when it heats up to a certain point The oil starts to foam those tiny bubbles slip past the valves you lose resistance the KDSS becomes ineffective like a blown out shock and The 4runner starts to act like it has no sway bars. Not a good situation. This is where reservoir shocks came from. Also this problem was amplified with the small lift in the TRD pro and is amplified more when you lift and increase wheel travel as it increases the stroke it increases the heat problem.
Another reason this system is a street cruiser system is you lose ground clearance in all the wrong places right in the front and right off the tale of the housing in the rear the system is vulnerable off-road. And very heavy.
A KDSS equipped vehicle has lower ground clearance than a standard 4runner how does that make sense for off-roading, it doesn't because it's not designed for off road.
The system is extremely heavy , outdated and will be replaced with a more modern version using electronics, again designed for the street crowd.
The KDSS System had its place it was a nice addition to the Lexus , as the years go on people will be tearing off these KDSS systems like previous generations removed rear air lift , xreas suspensions. it's just too complicated , limits your ability to modify and wait till you need replacement parts ! Oh man
Another reason this system is a street cruiser system is you lose ground clearance in all the wrong places right in the front and right off the tale of the housing in the rear the system is vulnerable off-road. And very heavy.
A KDSS equipped vehicle has lower ground clearance than a standard 4runner how does that make sense for off-roading, it doesn't because it's not designed for off road.
The system is extremely heavy , outdated and will be replaced with a more modern version using electronics, again designed for the street crowd.
The KDSS System had its place it was a nice addition to the Lexus , as the years go on people will be tearing off these KDSS systems like previous generations removed rear air lift , xreas suspensions. it's just too complicated , limits your ability to modify and wait till you need replacement parts ! Oh man
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Intruder
New member
Blah blah blah. I see lots of FUD and no facts. I guess I should stop taking my "street cruiser" off road.
To all the KDSS fanboys out there, it's not a personal attack on your decision or your vehicle when I'm giving your facts , of course you could take it off Road, you could take a limited off road with stock tires. I'm just giving you the facts about this system and why it will be gone and will suck to repair in the future.
Flame on !
Flame on !
Nope
You're right that the system opens and closes a valve to modulate the swaybar stiffness. What you're missing is that there are two stiffness settings. This means the valve is either full open or full closed. This creates almost no heat since either the fluid flows freely or not at all (it is not a shock absorber/damper).
How heavy is the system again? Please cite numbers.
I'll give you the ground clearance argument. Recall that the KDSS system ran back to back (same vehicle with new paint) the Rubicon and the Baja 1000. That is more than any TRD Pro ran and any KDSS vehicle can add aftermarket shocks for less and be more 'off-road' capable than a factory pro.
Addition to the Lexus? You should do more research into the system before you spew that garbage.
Intruder
New member
You should look up the difference between fact and conjecture.
1engineer
Moderator
First, I drive a '15 SR5 with no KDSS. I had a '12TE with KDSS though.
Second, I engineer and design high pressure hydraulic systems for a living and have done so for the past 25 years.
Third, you have absolutely no idea what you are talking about with respect to the quoted post and specifically about the KDSS operation.
Simply stated, the KDSS hydraulic system is two hydraulic cylinders connected to valves and accumulators. The system is NOT designed to be an actual suspension (very important) but to only control the stiffness of the sway bars by adding or subtracting force in a specific area of the swaybar, thereby causing a variable moment arm during normal operation. Again, it is not a vehicle suspension nor does it perform like one. It is PART of a suspension.
You mentioned reservoir shocks in your "factual" post above. I guess you meant to say that having a reservoir shock will help with heat dissipation because you expose more surface area to ambient temperatures correct? Is that what you meant to say? If so, what about the accumulators on the KDSS system? Are they not considered reservoirs? What about line length? Will the extended lines not act as reservoirs and radiate heat to ambient? So that shoots your "fact" (lol) that the KDSS will get hot full of holes because the KDSS system effectively has LARGER reservoirs and longer lines to cool the fluid! That is assuming though that KDSS hydraulic fluid would get hot like a suspension shock (your words) but it won't. Why? Because the KDSS cylinders don't move like suspension shocks. Remember that all they are doing is providing a variable moment arm to the sway bar. In normal operation they hardly move! Tough to create heat in fluid if no work is being done.
Now let's talk about foam in the KDSS hydraulic system. Those "tiny bubbles" (again your words) won't "slip" past the valves as you say. If, and that's a big "IF," you get air into a hydraulic system you create cavitation. Remember air is easily compressible and hydraulic fluid only compresses around 2% every 5000 psi. What will happen to air bubbles in hydraulic fluid compressed at those pressures is an implosion of great force. This implosion of an air bubble is strong enough to pull the chrome off of a rod or pit a sintered bronze port plate. We take cavitation seriously and design the system to prevent this. We also run specific additives in the fluid that will not let the oil foam for any reason. You can read more about this here: https://books.google.com/books?id=B...#v=onepage&q=antifoam hydraulic fluid&f=false
KDSS has been thoroughly tested. It does not get hot. It does not foam. It is not your tractor three point hitch attachment. It is not a log splitter.
Go buy a gallon of KDSS fluid. It costs a bunch. Why? Because it is an engineered specific fluid for that application and those fluids cost $$$. You can't get a 55 gallon drum at Tractor Supply. If you want to post your opinion fine. KDSS hydraulic system operation is not opinion though so you might want to read a bit before you join in.
