T513

I noticed twice yesterday my transmission downshifting by itself going down hills when I tapped the brake. The first time it was 5th to 4th. Is that normal, it definitely felt unnatural.

2008 is250 awd ~84k miles

Petet

timmy0tool

iTrader: (7)

my car does it too and I understand it doesn't feel normal.
it really depends on what load the engine is experiencing for the trans to kick down a gear under braking, but it's entirely normal.

put the car in ECT PWR (press the button to the right of the steering column) and see if there is a change in downshifting.
for sure it will change the upshifting!

T513

Good to know, thanks..
I could search but would leaving it PWR affect mpg? The car is already thirsty..

EZLex

I believe its normal. Does it in ECT PWR too, i always leave mine on. I always thought it was the the car using engine braking to help slow down.

Gville350

iTrader: (10)

Completely normal.

MNEWGEN

My 11 IS350 does the same too so that's normal. Once you step on the gas, it'll shift up itself

2013FSport

iTrader: (2)

At speeds over 60mph, on a declining grade, it takes a lot of throttle to get back to 6th. The hill in question is very repeatable. Placing in S mode reduces this a lot but sometimes it jumps down a gear or two just getting to S.

For the most part I get it into S while climbing the hill so that when I crest the hill I have it in a desirable gear and won't downshift from brake taps....

OP - yes, completely normal.
Try it!

timmy0tool

iTrader: (7)

from my experience going into S mode always results in 4.
this means if you're cruising at highway speeds above 60mph, going into S mode will downshift you into 4th!
if you're at city speeds under 40mph, going into S mode will still show 4, but will only shift up to that point until you manually shift up.

peanut220

i noticed what you’re saying too. My 06 is350 downshifted to 4th and it holds It for about 0.5-1 mile some times before hitting 5th then 6th is this normal? Then sometimes it doesn’t. No matter if I let of the gas or tap it doesn’t change it. Only flooring it hard will. This is in hilly terrain only. On normal grades it’s perfect shifting.

2013FSport

iTrader: (2)

Another thread on the same topic....
Brake tap induced downshift
https://www.clublexus.com/forums/is-...ue-or-not.html

Mine is very consistent >50mph if in 5th, stays in 5th. If in 6th, stays in 6th.
If <40mph, 99% of the time it limits at 4th. When below operating temp and crawling it may go to 1st or 4th.

Mods: if you stumble upon this, maybe merge this thread into the linked thread?