I bought my is-f used with about 23k miles on the odometer. Ever since I've gotten the car, I've noticed that the shift from 2nd to 3rd gear has been a bit more jarring than the other gears. This is especially the fact when the car hasn't been warmed up yet, the shift from 2nd to 3rd is very abrupt and seems shift with a thud and not as precise as shifts from different gears. Once the car has warmed up, the issue is less pronounced but still there is a disparity. Is this something that is common with the car or should I be concerned with it?

 

Exactly the same on my car.

It almost seems during the up-shift to 3rd it actually feels like a downshift - it sort of catches me off guard every time cause I'm not expecting the lag.

 

I have noticed the abrupt upshift from 2-3 in manual mode, sports mode on, but only when the engine/trans is still warming up and using 50% or less throttle. It feels similar slamming gears in a true manual transmission.

Once warmed up, it's smoother. Under 100% full throttle and shifting at the beep, it's much smoother. I think manual+sport mode is just that way.

Another thing I've noticed is when in manual mode, slowing down to a stop, and letting the transmission downshift on its own, the downshift from 2 -> 1 is really harsh. Harsh to a point where I have to adjust the brake pressure because engine braking increases at that point. Anyone else notice this?

 

The transmission shifts differently from 1-2 than any other gear as well. It has something to do with the way the Lexus set up the cars transmission and torque converter. It states somewhere it uses the torque converter differently for 1-2 then 2-3 and so on.

from the Lexus site: "in manual sport mode, the torque converter locks up in every gear except 1st gear"

 

http://www.lexus.com/models/ISF/feat...nsmission.html

Watch both videos on right

 

Same here.

~Dv8

 

Watched the videos, I'm still not sure exactly how the transmission works. What exactly does that torque converter do? What is the advantage of it locking up from gears 2-8 and why would it not do the same for 1st gear.

 

My only guess is that 1-2nd is so short compared to the others different things are needed??? Maybe someone with more transmission experience will chime in.

 

The torque converter takes the place of a clutch. It transfers power from the engine to the transmission.

It does not lock up in first gear to allow the car to get moving while allowing some slip. If it did lock up in first, the car would stall when you were waiting for a light to change. It locks up in the higher gears like the clutch does in a car with a manual transmission.