b407driver
New member
KDSS 'lean' issue: mostly solved
Regarding the KDSS lean issue, several people have PM'd me with questions about it, so thought I should document the relatively successful fix here.
Measuring fender heights at the center of the axle on level ground, as delivered my 'TRD Trail' measured:
That same day I walked out on the lot and measured all three stock KDSS vehicles they had on the lot, and they all measured about 3/4" high on the left-front, and about 1/2" high on the left-rear; this is an odd feature (or bug) of the KDSS system, that it, in and of itself, reverses the lean compared to non-KDSS vehicles.
Anyway, after a lot of research here on left/right leans with KDSS/non-KDSS vehicles (i.e. KDSS vehicles tend to be high on the left, non-KDSS vehicles tend to be a bit high on the right), I decided that the TRD Pro shocks being asymmetric must be exacerbating the 'normal' KDSS lean (i.e. the left shock is pre-loaded by 1/2" to supposedly compensate for the 'normal' 4Runner's left lean due to fuel/driver weight).
I thus requested the dealer swap the L-R shocks on their nickel, and accepted the responsibility if it didn't fix the problem (i.e. it was the dealer's last attempt to fix it, being that the TRD Pro suspension is not recommended for the Trail with KDSS). Fortunately for me, it has leveled the vehicle to near specs (roughly), and it now leans to the other side, but it is now not visually noticeable:
For those of you who noticed the rather large change that simply switching the shocks in the front made, I'm as puzzled as anyone that it effectively changed the lean nearly twice what I expected, i.e. a net change of 2.4" in the front and 1.8" inches in the rear, especially given the fact that no changes were made to the rear whatsoever (the TRD rear shocks are identical). The OEM shocks that were removed, both front and rear, are identical to each other.
After this endeavor, it's my belief that the KDSS system somehow levels itself front-to-rear, based upon some initial (pressure?) set point that it seems to 'like', the calibrating of which seems to make little difference. The system effectively 'knew' that the front had become higher on the right, and self-adjusted the rear to also be high on the right. I suppose considering what the system is supposed to do for high-speed driving, it makes sense that it would do this, despite me not being able to technically explain it.
If anyone were to do this again, I'd suggest either:
Hope this helps someone who may go down the 'TRD Trail' road in the future.
Regarding the KDSS lean issue, several people have PM'd me with questions about it, so thought I should document the relatively successful fix here.
Measuring fender heights at the center of the axle on level ground, as delivered my 'TRD Trail' measured:
- 1.5" high on the front-left
- 1.2" high on the rear-left
That same day I walked out on the lot and measured all three stock KDSS vehicles they had on the lot, and they all measured about 3/4" high on the left-front, and about 1/2" high on the left-rear; this is an odd feature (or bug) of the KDSS system, that it, in and of itself, reverses the lean compared to non-KDSS vehicles.
Anyway, after a lot of research here on left/right leans with KDSS/non-KDSS vehicles (i.e. KDSS vehicles tend to be high on the left, non-KDSS vehicles tend to be a bit high on the right), I decided that the TRD Pro shocks being asymmetric must be exacerbating the 'normal' KDSS lean (i.e. the left shock is pre-loaded by 1/2" to supposedly compensate for the 'normal' 4Runner's left lean due to fuel/driver weight).
I thus requested the dealer swap the L-R shocks on their nickel, and accepted the responsibility if it didn't fix the problem (i.e. it was the dealer's last attempt to fix it, being that the TRD Pro suspension is not recommended for the Trail with KDSS). Fortunately for me, it has leveled the vehicle to near specs (roughly), and it now leans to the other side, but it is now not visually noticeable:
- 0.9" high on the front-right
- 0.6" high on the rear-right
For those of you who noticed the rather large change that simply switching the shocks in the front made, I'm as puzzled as anyone that it effectively changed the lean nearly twice what I expected, i.e. a net change of 2.4" in the front and 1.8" inches in the rear, especially given the fact that no changes were made to the rear whatsoever (the TRD rear shocks are identical). The OEM shocks that were removed, both front and rear, are identical to each other.
After this endeavor, it's my belief that the KDSS system somehow levels itself front-to-rear, based upon some initial (pressure?) set point that it seems to 'like', the calibrating of which seems to make little difference. The system effectively 'knew' that the front had become higher on the right, and self-adjusted the rear to also be high on the right. I suppose considering what the system is supposed to do for high-speed driving, it makes sense that it would do this, despite me not being able to technically explain it.
If anyone were to do this again, I'd suggest either:
- Switching left and right shocks from the get-go; or
- Buying two right shocks (no change in the stock perch setting), which I believe would nearly level the vehicle perfectly. Being that the only reasonable way to have TRD Pro suspension is to buy the $1700 front-rear kit, this probably isn't an option for anyone unless they buy the front and rear shocks separately, which would be prohibitively expensive; or
- Last option would be to move the perch setting on the left shock to be equal to the right, though not sure how difficult this would be.
Hope this helps someone who may go down the 'TRD Trail' road in the future.
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