07-IS350

Just called Lexus service department about the IS350 auto transmission.

I asked if the car had a lock-up tourque converter. My previous 3 cars did have that feature and I noticed when travelling at a speed around 60 or so the tach would barely move when I took my foot off the gas or sped up. The advisor didn't know but will find out.

With this car I notice that the tach moves quite a bit when applying the gas or taking my foot off the gas at a similiar speed of 60 mph or so.

The advisor did mention that built into all Lexus' transmissions was the feature where the transmission would act similiar to a standard trans in that going down a hill it would "drag" somewhat. When I go down a long grade I don't notice that at all unless I move the shift lever to the right position and lock the transmission in 4th gear.

Any thoughts out there?

IS350jet

No lock-up converter. The ISF has one, though.

07-IS350

Well, thats 2 Lexus advisors that say "yes" it does have a lock-up tourque converter (from different Lexus dealerships) and 1 reply saying no it doesn't have a lock-up tourque converter.

Anybody else wanna chime in?

llamaboiz

i wish i could get a B&M high stall (2800rpm) torque converter

Audiofan2

When going down hill (particuarly long grades) I have occasionally had to take a quick stab at the brakes due to a truck or curve ahead. When I do the transmission does seem to "drag" and hold a lower gear to keep speed constant. I have noticed that the gear indicator will sometimes indicate a reduction in gear, however many times the gear is held higher, just with some type of drag.

A separate issue I brought up last year is that when you are in 2nd or third using the paddles to hold a gear but only barely applying throttle between 2-3k rpm the engine will spontaneously drop about 500 rpms. others said they have had the same issue, dealer new ones had the same problem with no fix. it is very annoying to get the sudden drop though.

ba-b4

yeah when I go down long hills my transmission also downshifts... I don't know if this is by design or not but if it is I'm guessing it's to save your brakes from overheating and instead use the engine braking instead? Anyway I don't like it so all I do is shift it to manual mode and upshift the gear back myself with the paddles.

eddo1

The transmission is designed to slow the car if it senses you're going down a hill and you step on the brakes - it activates "grade logic" I think that's what they called it to slow down the car. Lexus had the same thing on my 99 ES300. As for lock up torque converter, I'm not sure but I think it does. The IS doesn't seem to coast very freely when you let off the gas as compared to my highlander.

lobuxracer

iTrader: (2)

Contrary to previous statements, the ISx50 definitely have a lock up torque converter:



They also use the computer to provide "flex" control:



Finally, to end the speculation, the transmission responds to road conditions as described below:



Subscribe to TIS. Read the New Car Features manual. You'll learn a LOT about your car.

tps3443

So the A650E is a great tranny. Just not great to swap in to non vvti sc400's

Im looking forward to the A650E in my ultra clean 98+ sc400 im buying. My previous 95' SC400 with the A340E was smooth as butter. It was a tough transmission, though it kinda felt like it would stumble around to pick the right gear.


This was an amazing thread. And no one else has done it! Lol

2013FSport

iTrader: (2)

Wholly resurrection Batman......
Pretty much all Auto's made since the 80's have a lock up T/C.... It's the only way the manufacturers meet Federal EPA standards across the fleet.
Obviously in ECT mode these things drop out of Lockup at the drop of a hat.

Anywho, other than Lobu's post from the past, not a lot going on here....