Auto Gearbox Question

[Mikhailovich]

Hi guys, I am new to this forum. Got my new IS250 two days ago and just want to add it's bloody brilliant :)

I been looking to the answer to this question as well since, well yesterday. Never drove an automatic until now and the nifty paddle shift meant that I soon started to override the automatic when it came down a hill. Yes i was taught the old-school way; gear-braking, double de-clutching, etc. All this new tech right now is rather overwhelming. It's been a pleasure then to see so many intelligent comments on here that I had to just create an account and follow-up! After following this thread, from my judgement I think you guys have nailed it. In particular the last comment:

As long as the IS250 does use engine braking then OK, but I do wonder if it uses it enough to maintain the right engine speed relative to the road speed. It seems to me to be engineered to coast a long way, maybe for fuel saving. So it might well be safest on steep hills and wintery roads to used manual control.

I think you're absolutely right, the IS does seem to aggressively stick the gear higher very quickly from my experience driving it so far (5th gear at 30mph?) - how else can it get these remarkable fuel consumption numbers vs its engine size? In its haste there's a lot of 'engine slack' when going downhill, hence my reflex to just stick it down a gear or two.

I also wanted to know whether doing this will damage the transmission and after reading this thread I think I can conclude it's not going to damage the engine/transmission as long as the engine is not massively over-revving when you knock it down the gears (i.e. the accelerometer in the red) - unless someone here comes up with some solid evidence that it does of course! However the sole purpose should not just be braking, it should ultimately be a balance between safety and control and that's why I think it's necessary due to the aggressive nature of the automatic gear shifts. After all those paddles are just so damn cool, it's literally begging you to micro-manage and override the automatic whenever necessary!