baldrick

torque converter clutch is controlled by 2 valves: one is hydraulic, the other is electric. The electric one is a solenoid and controls the flow of oil pressure to the hydraulic valve which leads to the clutch inside the torque converter. Both the TCC apply valve and the solenoid are in the valve body usually.

Sometimes the fault is from water ingress into the harness connector at the transmission case. so first unplug and blow the connector dry. look for any sign of water going into the harness loom by checking for wetness. if you find anything, the water source needs to be found and stopped. I have seen plugged windshield drain and a small leak in the firewall causing this in a VW Passat (whole TCM insides had turned green). I have also seen badly contaminated ATF causing numerous electrical solenoid faults. But that is resolved by a flush and fill, and valve body clean.

The TCC apply valve gets a lot of work if your commute is in stop and go traffic since you rarely get into 3rd or 4th gear. Likely it is the valve which wears the most in these commutes. So if the harness is fine and you have a spare car, only fix is to pull the valve body and send it off to http://www.valvebodyxpress.com/ and they can trouble shoot it.

sophee24

I have an 08 GS350 as well- has 87,000 miles on it.. I'm getting the shudder between 20 and 30 mph--Dealer said trans need to be replaced little over $5000...not sure what I should do

Willp79

Mine is the 08 gs350 it stutters between 20/25mph.I tried changing my transmission fluid .it drove smoother but didn't go away.I have not had the dealer check it yet.some people say it is the torque converter.idk so I bought the extended warranty. What did u do?

Willp79

[QUOTE=sophee24;9202506]I have an 08 GS350 as well- has 87,000 miles on it.. I'm getting the shudder between 20 and 30 mph--Dealer said trans need to be replaced little over $5000...not sure
I got my transmission fluid changed.the car did ride smoother but problem is still there.seems to go away when the car has been running and is heated up.some with similar problem says it is the torque converter.I have not had it checked.to be on the safe side I perchased an extended warranty.

Willp79

Does yours go away when it has been running for a while ?

MnGs3xx

Mine never goes away i have the exact same symptoms it only happens under light acceleration 1500rpm and going anywhere between 20 to 30mph both my 3rd and 4th gear do it

sophee24

I haven't done anything yet- the car does it no matter what the temp is or how long I'm driving it.. I heard something about torque converters going bad in these cars...but the dealer says tranny needs to be replaced. They did they I could "drive through" the stutter but don't know how long the car will last...

On a side note- My transmission fluid has been flushed and replaced around 80,000....car has 87,000. So it's not that.

It feels like I'm driving over rumble strips...

photoman1

I'm having the same issue.
I have a 2006 GS300 with 146,000 miles. Like most people the dealer says I need a new transmission. Any Suggestions/Solutions to this problem?

xbladex00

If you were too lazy to read... A couple of solutions were (I THINK FROM CHEAP TO EXPENSIVE)

- transmission fluid flush & differential (I would say $100-$300 if you get a shop to do it )
- new ECU
- new torque converter
>>>>>> not sure which ones cheaper tho
- new transmission ( from reading the posts $6,000)

PoppFlyy

Hey guys.
I had a similar problem recently with my 06 GS300 with 70K miles.

My car felt like it was 'braking' after I hit and let off the brakes.

I took my car to Lexus of Westminster service department and It turns out it was actually downshifting in error.
Long story short they ended up swapping out the ECU. I also did the transmission and differential oil change right after they fixed the problem and now my car shifts like brand new.

It's a problem that Lexus is aware of.
For those of you in or around Orange County California Lexus of Westminster is far and away the best Lexus dealership for service.

Good luck!!!

NJ07gs350

Hey guys.
My 07 GS 350 AWD "had" the same issue i bought the car this past july with 149K on the clock.I swapped out the plugs and these exact symptoms are gone. Just thought i'd share it worth a shot, got the OE plugs from amazon and did them myself. any questions just ask. hope this helps out

Kashill

Any updates on any of these fixes (new plugs, ECU, converter, trans and diff flush)?

xbladex00

Is there a specific spark plug socket thats needed? I'm planning to do this soon too.

MnGs3xx

The torque converter is in the sealed transmission which is why they recommend swapping the whole tranny and not just the torque converter... id doubt the ecu is the problem because its a mechanical problem i couldnt imagine swapping the ecu would get rid of a shake thats obviously coming from the tranny... as for the spark plugs it would give similar symptoms but in my case and other the stutter/shake happens and a certain speed and the rpms are steady so its not that either

ez12a

I'm not expert in transmissions but I believe the ECU handles the shifting logic of the transmission including clutch lock-up. That in addition to faulty or clogged solenoids that control shifting, I can see how a bad ECU (faulty capacitors, etc.) can cause inconsistent performance.

Swapping for a new/reman ECU would theoretically solve two issues: outdated shift logic firmware, and/or bad hardware.

There are people on this board that have swapped transmissions to no avail.