I just got off the phone with a Lexus specialist in the Houston area. They are a 3rd party service rep that was started-up with former service reps and mechanics from Lexus.

I asked them if it would make sense to do a tranny change at 60K, and he said it doesn't. He is also of the belief that although it is "lifetime" fluid, he recommended that an owner changes it at 100K.

He did; however, recommend an owner change the diff fluid at 60K.

 

Hmmm. On that note, has anyone changed the diff fluid with Mobil Synthetic diff fluid?

 

Hi all, I have a 2013 GS and I'd like to change the transmission fluid. The 6-speed in my car is similar to the 3GS so finding a DIY isnt the hard part..generally doing a drain-fill isnt hard, just gotta find the correct 2 bolts. What i'm confused with (maybe the 3GS forum is a better venue) is the temperature testing...why is there a need to test temp to get the right fill level? If a measured drain is performed and a measured fill occurs there shouldn't be a problem. Hell, even if you're off by half a quart in a 7-8 quart system its not a huge deal, right?

I come from VW's and DSGs where a similar procedure is performed (car in the air, bring trans up to temp, open drain hole and let excess drain). But we learned that if you measure what you take out and put the same amount back in there's no harm.

Maybe I'm missing something here, hopefully someone more knowledgeable than me can chime in.

Thanks

PS - Lets not get into an argument about "lifetime fluid", everyone has an opinion. Coming from German cars, I change fluid so I don't have to change parts. And, it doesn't hurt.

 

Great question, and I agree with you about the fluid. I've been looking for a Toyota/Lexus shop that will do just a drain/fill, but they all prefer their flushing machines.
The reason why you need to watch the temp, is because the fluid expands slightly when it gets hot. I watched an Infiniti Tech do a drain/fill on a 7spd and there was only one plug for draining and filling. The majority of the service was spent watching the temps get in range. Usually you are able to only get 4qts out.

This is a very technical video on the 6spd auto's in Camry's

This guy just drains/fills:

Let me kno what you find out

 

Its too cold out now but I plan on doing a measured drain followed by a measured fill. The toyota design is exactly like VW's, only we call it a snorkel vs straw. The key here is to leave the new fluid in the garage, drive the car onto ramps/stands at night, leave it on them all night and do a cold-drain/fill in the morning. If you put in what you took out, PV=nRT ensures that you will be at whatever factory spec your car was filled at. If you trans was under filled at factory you will under fill and vice versa.

For what its worth, something like 2-3 quarts come out of our transmissions when you drain and fill. The trans holds a total of 7-8 quarts. So overfilling by 1/2 a quart is being off by 6%. (05/8 = 0/0625),

 

Some many years ago it was typical for automatic transmission fluid operating temperature to run 200F or higher under normal driving conditions. Some vehicles even had a common operating temperature of 220F or higher. Nowadays however transmissions are designed to operate at much lower temperatures, which not only extends the life of the transmission itself but also extends the life of the transmission fluid. Typical transmission fluid temperature in new vehicles is only 150F-175F under normal driving condition. This is why the newer vehicles don't require automatic transmission fluid replacement in the service requirement, regardless of mileage or age of vehicle. And further, this is why many of the newer vehicles don't even have an automatic transmission fluid dipstick...

Fluid Temp - Life of Fluid
-----------------------------------
150°F - 150K+++ Miles
175°F - 100K Miles
195°F - 50K Miles
220°F - 25K Miles
240°F - 10K Miles
260°F - 5K Miles
300°F - 1K Miles

 

If you do decide to do 'Drain & Fills' you'll need to do at least a few of them to get where you only have ¼ of the old dirty fluid remaining.

I do not know the fluid capacity offhand of the GS 350 transmission, but a typical automatic transmission holds about 9-10 quarts from which you can usually drain about 4 quarts of fluid. This would provide the 1st D&F to replace 40% of the entire fluid, but leave 60% old dirty fluid remaining. And the 2nd D&R leaves 36% old dirty fluid remaining, the 3rd D&F leaves 22% old dirty fluid remaining and the 4th D&R leaves 13% old dirty fluid remaining. - (The math is 60% x .60 = 36% x .60 = 22% x .60 = 13%.)

If the fluid capacity is greater than ~10 quarts or if the drain amount is less than ~4 quarts, then the number of 'Drain & Fills' to accomplish a reasonable fluid replacement increases.

I think there is actually a benefit to doing 'Drain and Fills' in lieu of flushing, especially if the transmission fluid is really old or has been overheated or subjected to extreme use. Flushing can often 'cause' transmission failures where there was no failure before. The reason this can sometimes happen is because a flushing will fill the transmission with 100% new fluid that can dissolve old fluid varnish and trapped dirt/slush within the transmission, which in-turn can cause bits of varnish and trash to clog up the tiny orifices and ports within the transmission causing failure.

See the attachment below for a nice Excel 'ATF Drain and Fill Calculator' that can be modified (in the Excel Cells C5 & C6) to reflect any vehicle's transmission capacity and fluid drain amount so you can see the number of D&F you'll need to accomplish.

 

So if you have this done at Lexus, do they drain and fill or flush?

 

Lexus will completely flush the transmission and it will have 100% new fluid all in one event. The 'drain and fill' is a DIY method done over a period of time - anywhere from each individual D&F taking place hours apart (with the vehicle purposely driven ~100+ miles to mix the old and new fluid and dissolve some varnish/trash), to months apart (where the vehicle is driven thousands of miles) between D&Fs. When doing D&Fs the idea is to get the fluid replaced to a percentage of 75% or more over a period of time where the new fluid mixes with the old...and each subsequent D&F becomes a fresher blend of the new and old fluid, with the goal being that the old fluid becomes a minor percentage of the fluid mix.

 

Yes, that is what I used in mine. I have a how to video in the link below.

 

What does the word "Lifetime" mean?
I have had 5 cars with over 100,000+ miles each.
On the other hand,
my mother has a 86 Lincoln Town Car with 50,000 miles and still ticking.
Even if they specify a set mileage for fluids like 10,000 miles for oil changes is that the same for someone that drives to the tach redline before shifting as for a person that never hits 5k rpms when they drive.

Yes the fluids should be changed because of age but the car is parked in the garage and looks like a 3-5 year old car

 

hey guys just wondering if anyone has changed their tranny fluid. one dealership told me its never needed and one is telling me its time to do it.

 

When I was looking into buying a GS I watched a few videos about this....

I've already decided its way too much of a pain in the ***, particularly if you don't have access to a lift to keep the car level. My driveway is inclined slightly and my garage is way too small to actually work on a car while it's in the garage... so its out of the question for me. The problem is there's an intricate procedure to make sure the fluid is at the proper level and you have to get the fluid up to a certain temp to even make sure of that... and from what I've read, under or overfilling the thing is bad news. When the time comes I'm probably just going to try to find a transmission shop that does these all the time, or even shop dealers to get trans and diff fluids changed... I'm planning on a 50K-60K interval for that service, unless someone whose a transmission god can convince me it should be more like 30K.....

The rear diff fluid by itself, IIRC, isn't nearly as sensitive so that might not be a bad DIY job if you have a lift. That was basically "lift car, dump fluid fill with appropriate amount, done". There may have been more
steps than that, but that was downright straightforward compared to actually doing the transmission itself.

-Mike

 

I had it done at the dealership at 60,000 miles.

 

How much did they charge you to do it? Did you get the diff(s) done at the same time?

-Mike