gs350fan

So likely torque converter shudder. I used to work for Ford, same problem, you would exchange the fluid and it would go away. Shops like to replace torque converters for this problem, but it is friction modifier breakdown.

DaGunit

ibidu1

iTrader: (1)

Awesome great that you found some improvement! Your next fluid change how about you drop the pan and replace the trans filter and clean out the magnets.

gs350fan

There is a video by a Ford tech, Ford uses a version of the ZF sealed transmissions now which are quite similar to ours. He says pretty much the fluid gets dirty, gets full of metallic flakes, and all the electronics bathe in that fluid. It can change conductivity of the solenoids, clog solenoids, cause shudder, etc. Lifetime to a carmaker is the length of their longest extended warranty, so 120-150K. By that point replacing anything is fair game. They have to make money too.

He uses a Ford unit as an example but everything said pertains to us.

ibidu1

iTrader: (1)

gs350fan ya I love that guys videos and have been viewing him for many years. He knows his stuff!

DaGunit

Thanks for sharing! Very interesting~

Not sure if I'll be draining the fluid again. If I keep the car, I'll likely do it one more time and if that is the case, I'll drop the pan and do the whole thing more thoroughly as you suggested (ibidu1). Now the shudder is nearly gone and certainly tolerable (when I do still notice it) but there is still a light vibration in the steering wheel when coasting (even in N). Plus, the pull is still there but not drastic. I'm starting to think I had two problems simultaneously and now I probably need to look at the suspension bushings as ibidu1 originally suggested. That would explain the light wobble/vibration, uneven tire wear, and probably why it made diagnosing any single problem so difficult to everyone who has looked at it. To me, it is easier to isolate now that the shudder has drastically improved.

I'm not trying to turn this into a gripe thread but I have been pretty disappointed with the probs (both read about and experienced first hand) that come along with these Lexus AWD systems and some of the probs only specific to the GS's. If it was a solid car WITH these few mods I have done, I'd be game for investing the time/money into it. However, this car doesn't seem to play nice with modifications and Lexus doesn't offer anything stock that excites me enough to stick around. So, if I do end up deciding to part company, it will likely be to switch to a different manufacturer.

I have really enjoyed my Lexus vehicles but Lexus has got to do a better job keeping up with the competition. They had many years to get the 3rd gen GS right by 2010. I've been chasing cabin noises/creaks/rattles in this car nearly since I bought it 5 years ago. Maybe I just expected too much from Lexus after the great experience I had with my 99 GS 400 but the GS350 awd always left something to be desired (in my experience of course). Plus, I miss a v8 with an exhaust!! Not looking good for holding on to this one at this point.

gs350fan

I talked to a transmission guy today about these cars. He is a big rebuilder in the area. Of course we know these trans are the same as the Tundra. I'm just quoting him:

He said the transmissions are wear item, run VERY hot and they are constantly shedding
The torque converter linings are thin and delicate
It is not pretty when they fail, eventually clog the valve body and that deprives pressure causing lots of other thing to fail.

He suggests a yearly service. His opinion - WS fluid isn't enough for these transmissions, MAYBE if renewed yearly.

DaGunit

Well that sure doesn't sound good. Hopefully this info will encourage more people who want to keep their GS's for a while to pay heed to this suggestion because when I asked my service "adviser" about a transmission service, I too, was told it was unnecessary until over 100k and skipped it (not even thinking to cross reference that with the forum). Doesn't seem as though that is sound advice.... esp given my research as of late.

gs350fan

What is "Lifetime"? Life of a Dog? Cat? Car?

Lifetime to an automaker is the length of their max extended warranty. After that (like 120K or so) they want you to spend money again. Maybe the fluid could last longer, under very ideal conditions. Drive on hills? Live in Arizona? Have a heavy foot? you get the idea. It isn't lifetime anymore. Also, longer fluid service intervals reduce oil consumption, which is good for the environment and they may even get some credits to that end. I know Ford publishes "Severe Service" schedules, and no fluid is lifetime under those conditions.

If they did publish an interval, people would complain about the cost.

I am probably going to install a trans cooler. No reason not to.

ServerTech

Good luck installing a trans cooler, I want one too!

ibidu1

iTrader: (1)

Interesting I never knew the 2wd was the same as the v8 tundra/Sequoia if anything this is a good sign for us GS owners as the transmissions are beefed up and very stout for a lighter GS platform. As far as WS there have been people to swap out the WS for Amsoil, there are many who have had good luck with it and claim to have way better shifts from switching to the fluid.

Personally I never liked running an aftermarket transmission coolers, the benefit doesnt justify the reward. Aftermarket coolers are not as reliable as OEM setup, and if you get a leak from a hose or a loose hose clamp, then your risk for destroying the transmission is greater. Our oil cooler fins do get dirty and clogged if you simply pressure wash them I think it will help cooling. If you do replace the trans cooler with aftermarket, I think mishimoto kits are pretty stout, of course you can build your own kit with AN fittings and stainless steel hosing.

Drcoffee

DaGunit