aristo1987

tranny doesn't need to br dropped. I had a shop do it for me.

gs350fan

I come from the world of Fords and this is very common in some types of Transmissions. Like the ones that went into Crown Vics and Trucks (search 4R70W shudder, see what comes up in the ad on google!). The problem is fluid breakdown, as well as the torque converter clutch. We had Ford engineers come on Forums and explain it to us in depth. These cars are designed so the TCC slips a bit before lockup, to reduce vibration and maybe gas mileage. The slip may be 4-8 rpm, but it isn't a full lockup. There is feedback from the speed sensors to modulate pressure from the solenoids so it is in that state. The fluid has friction modifiers that prevent binding while the slipping takes place. How do you explain it? Imagine trying to separate two pages in a book. It is difficult with two dry fingers, you may not be able to or it will "shudder." Now wet your fingers, and it works. In a car you feel the rumble strip effect.

There is a product called "dr tranny instant shudder fix" which may work for this problem. It is very rare to replace a TC for that reason. Also, a complete fluid exchange (the Ford Transmissions use a different fluid, but a Common Fluid like Maxlife ATF may be an option).

Other issues could be dirty fluids blocking the solenoids from applying correct pressure.

gs350fan

Oh, one more thing, misfires can cause the exact same issue. I don't know if the Lexus scan tool can read raw misfire counts but that should be eliminated first. If the shudder goes away by touching the brake(that disconnects the TCC), then it is likely the transmission.

NikS

Maybe it's a throttle position sensor? Easy to change and about $60 on Amazon

aristo1987

nope . done that waste of money.

DaGunit

gs350fan

No code, because misfires much reach a high threshold for a code, and the sensors see no problem. You won't even get a transmission code because the commanded slip ratio is sustained, but the fluid or clutch is not allowing smooth slipping. The misfires may happen for a second and under certain conditions. With the 60K spark plug interval, they want to be sure misfires are an impossibility.

This is why a through diagnostic has to be done before any parts are changed. Another thing I suggest for these cars is a transmission cooler, especially in a hot climate. Such a heavy car is going to create high transmission temps and deplete friction modifiers. I installed large trans coolers (Hayden 679) on problematic ford transmissions and never had any issues, some up to 300K. Probably going to put one on mine very soon.

Mwest

This part information you provided is for a Toyota 4 Runner? It doesnt have assocation with Lexus GS350 transmission shift solenoid.
#3528030050 / 2004-2019 Toyota Pressure Solenoid 35280-30050

MyL3xus

Ever find a fix for this?