Quick question. does anyone know how the torque converter lockup behaves in the 8spd. Usually this is at a certain speed in a certain gear depending where the **** lever is... Some cars lock up only in the top gear you are in at the time. Some cars lockup more regularly... Wonder what the 350gs 8sp would do? I cant really work it out as there is so many gears

 

I'm not sure and can't answer your question directly..but....it's feasible that an Ultraguage II MX may be able to tell you when the converter is locked.

I have an Ultraguage II MX model in my 2015 Tacoma and there is an indicator (a 0 or 1 value) when the torque converter is locked or not. I have been considering installing one in my GS but haven't got around to it. Note that you'l probably have to program the unit to work, so it may not be plug and play. I have seen the codes to use, but without actually using them I don't know if it will work or not. I am saying this just to set the expectation that you'll probably have to experiment with programming it to make it work on the GS.

This unit also tells me the tranny fluid temp, along with a ton of other measurements, which I wanted to keep an eye on towing temps.

Based on watching the gauge and driving the Tacoma, I cannot tell when it's locked by "feel". Also one little change in throttle position or road grade will unlock/lock it. It appears like many factors come into play to decide whether or not it locks, at least on the Tacoma.

https://ultra-gauge.com/ZC/index.php...products_id=57

 

The torque converter may never lock up. The IS-F and GS-F specifically mentioned their "directshift" or something for their transmission. Such words or anything similar has never been mentioned for our GS350s' transmission, which leaves me the impression that such feature may not represent for our cars.

 

I cant imagine that it wont lock up... it is a fuel saving feature that is pretty easy for manufacturers to implement without breaking the bank...

 

Here is a description of the lock converter logic, note the second panel indicates that the lock up is not going to be all or nothing.
It can be locked or partially locked to suit conditions. Quotes from Lexus Tech manuals

Lock-up Timing Control
The ECM sends current to the shift solenoid valve SLU (lock up control solenoid assembly) based on signals from various sensors and engages or disengages the lock-up clutch.

Flex Lock-up Clutch Control
Controls the shift solenoid valve SLU (lock up control solenoid assembly), provides an intermediate mode for when the lock-up clutch is between on and off, and increases the operating range of the lock-up clutch to improve fuel economy.

 

17' GS350 8SPD

Lock-up Schedule

Throttle Sensor Position
6%
Vehicle Speed
80 km/h (50 mph) or more
Shift Status
8th gear
Lock Up Status
ON
HINT:

Lock-up prohibition conditions:

• A/T oil temperature is below 5°C (41°F)
• Engine coolant temperature is below 50°C (122°F)
• Shifting operation
• Throttle valve is fully closed
• Stop light switch is on

 

This is excellent information about what is required for lock-up, and also provides insight into many other things (e.g. transmission shifting, throttle operation, HVAC heating, etc.) that require certain parameters to be met before normal operation can take place.

 

thanks. this makes sense. I wonder if you drive in manual mode if it will follow same kind of principles in different gears/speeds.

 

According to Lexus, the GS 350 and IS F both have the "Eight-speed Sport Direct-Shift Transmission" but I'm not really sure how different they are given the transmission in the IS F is under "F" duty.

Apparently, the IS F can lock up in gears 2-8:

Source

Not sure how this compares with the GS though and it was just about the only thing I could find about the "Eight-speed Sport Direct-Shift Transmission."

 

I think the "direct-shift" transmission only applies to full F cars, not F-sport cars. Which means the transmission may never lock up except in 8th gear in GS350. I wish the transmission can lock up in more gears but it doesn't feel that way. As someone who came from a manual Mustang, the AT in the GS 350 feels laggy and indirect.

 

Here's the full quote from the Lexus site about the GS 350 transmission:



It also has the "Direct-Shift" transmission, which is why I'm confused as to whether or not it has the same capabilities.

 

I know for instance the RX locks up from 2nd up to 6th.. But it is a different gearbox altogether

Would love some accurate info on this though!

 

I realize that this is reviving an old thread, but @BULLITT1 is there any chance that you can get me these same specs for a 2016 IS350 AWD F-Sport? I'm assuming you need Techstream/TIS to get this info. I would really appreciate it!