Brian231

Fluid Engineer in Lubricant Technologies, I fell off my chair laughin so hard at this. I think everyone raises some good ponts on this. All in all, I was told by Lexus that they designed these cars 2Gen to be very efficient and reduce maintenance dramtically.

sktn77a

iTrader: (2)

I realize that the science has moved forward since the 99 RX300 was designed but this car also said no transmission fluid changes are needed (unless under "severe" service conditions - then every 30k). The RX300, while generally being reliable, has had more than the background incidence of transmission failures, particularly around the 90-100k mark. So what they thought was an OK recommendation at the time (no transmission fluid changes) might not have been. Hindsight is 20/20, ten years after the introduction of the RX300; I wonder what we'll be seeing in 2016 with the ISx50?

And, incidentally, has everyone noticed the car manufacturers currently touting their "no service (other than engine oil and filter changes) for 100,000 miles"? Seems that, if you can't state this, you're at a comercial disadvantage!

Sean K.

Isn't it fairly obvious? If you never come in and have it changed, you'll have to buy a new transmission from Lexus when it fails. Now, which is cheaper, a flush and fill or a new tranny?

Sean

Sean K.

Again, you're sorta proving the point.....A sealed unit bearing doesn't require "service" yet they do fail....on a regular basis. Nissan was right. You don't have to do anything. You wait for it to fail and then you replace the WHOLE thing. And when they do, they aren't $7 for a race and another $9 or so for the Timken tapered roller bearing that's got a lifetime warranty and you can pick up from ANY parts store like Autozone or Checker. Last I checked for my Cummins 4x4, the sealed unit bearings per side were $360 at wholesale cost. I've seen then all the way up to almost $600 a side for the F350s. And they don't last the "Lifetime" of the vehicle any more than the old replaceable ones....in fact, they have a shorter life span in my experience. What this snake oil is really good for is those of you that don't do your maintenance when you should. Will a sealed bearing last longer than traditional wheel bearings for someone that NEVER packs their's? Yep, usually....unless you're running really offset wheels, larger, heavier tires or you see a lot of water intrusion (psst....they're not really 'sealed' if you submerge them).

Your 100K mile antifreeze sounds an awful lot like Dex-cool and similiar coolants foistered on unsuspecting consumers who end up with all kinds of sludge in their systems b/c they were duped into believing the "no service" hype. Sorry, it's really cheap insurance to just test the fluid and see if it actually needs changing rather than relying on some arbitrary mileage number that may or may not be accurate, especially depending on your useage.

The IS series transmission isn't magical and neither is the fluid. To think otherwise is to believe in rivers of chocolate and gumdrop rainbows.

Sorry to burst your bubble.

Sean

mir

Can you backup your claim about long tranny life because of frequent fluid change? Where is the statistics? Or is it that there is a perception that it will help so you believe it will? I would be happy to change my tranny fluid if your hypothesis has been proven. I guess it comes down to personal preferences too. If you want to change it, you are free to change it. But that does not mean it is required or even recommended.

Sean K.

To all the people that believe that the transmission fluid in the IS really lasts the 'lifetime' of the vehicle, I have to ask.....just how much mechanical background do you have with vehicles in general?

Just wondering......


Sean

Joeb427

iTrader: (1)

At around $50 a gal for WS fluid,the stuff has to be pretty good.
I'm still not comfortable with the "never need service sealed trans".

Sean K.

So, from reading this post, it would *seem* there is a procedure for changing the fluid, though it has to be done verbatim from this manual and obviously you need the SST (special service tool) in order to do it regardless. From what I can gather from the post, the SST is purely electronic. Doesn't seem to be the actual pumping tool to remove and replace the fluid.

However, all that said, it seems that in order to do this a MAJOR disassembly of the transmission is required and probably isn't cost effective vs. just waiting for the transmission to burn up and replacing it as a unit for what must be a significant chunk of change. If that is the case, it's an extreme example of p!ss poor engineering.

Can someone confirm my hypothesis? I am about to lemon law this car anyway and while I love it in terms of looks and performance, I'm really thinking it's an extremely unwise decision to repurchase something that cannot be economically serviced for such a critical drivetrain component.

Sean

Kurtz

iTrader: (1)

Nope. Read the fluid amounts there. The entire system holds a little under -9- quarts. Even replacing the torque converter (the higher volume fluid exchange on there) you're replacing about half the total fluid.

And of course the torque converter swap requires dropping the transmission anyway to get to it. (or the engine from the other direction)

This isn't exclusive to Lexus though, other companies are doing no-service transmissions too, it's becoming more the norm. Hell, there are BMWs that don't even have -engine oil- dipsticks anymore.

Sean K.

I did read the fluid amounts carefully. My question/hypothesis is clearly stated in the first sentence of the 2nd paragraph of my quote in your post.

What I'm basically asking is: it's not cost effective to actually change the fluid at (arbitrary) service intervals b/c you have to do major, expensive disassembly of the transmission, correct?

Thanks for any additional input you can give....

Sean

lobuxracer

iTrader: (2)

You can't change the fluid. You can replace a small amount of the total. The New Car Features (where the post originated) gives this procedure for replacing fluid when the transmission has been serviced in some way.

Transmissions have joined ball joints and tie rod ends as replace only items. Until 2002 it was impossible to buy internal parts for the V160 Getrag in the Supra. There are many Getrags in BMWs for which there are NO parts available except complete transmission swaps. And these are manuals!

If you absolutely insist on changing the fluid, you could machine a piece using the dimensions of the oil cooler, install it in place of the oil cooler, and do a complete fluid swap with a conventional fluid exchange machine. Some enterprising soul may actually do this at some point, but if anything goes wrong, Lexus will deny any warranty claim. They specifically say, DON'T under ANY circumstances (whomever came up with this severe duty 30k interval is not looking at Lexus documentation - this recommendation does not exist.)

Am I comfortable with it? As much as I can expect be. But I've only been building engines for street and competition since 1980. I'm not the foremost expert in the world on this stuff, but I can say even after 144k miles on my Supra, the shims the factory put in for valve clearance have not been changed because the clearances have not gone out of spec. So, I'm not entirely skeptical that their recommendation is bad at all.

Sean K.

Thanks for the input Lobux....I just am disappointed that I bought this car thinking that like my other 7 Toyotas, this would be a vehicle that would stay in the family for a really long time with zero problems. So far, I've got a minor recurring electrical problem and a transmission I was told could be serviced by Lexus and now I'm finding out it can't be. Granted, the transmission will probably last at least 100K miles....probably more if it's anything like my other Toyota vehicles. But at the same time, when it does tank, I really don't want to drop thousands of dollars into a new transmission for a vehicle that will at that point likely have little value.

It's just a commuter car for my wife that is very sporty looking and seems to be a really nice car.....just a little disappointed with the lack of foresight on Lexus' part (IMHO of course).

Like I said, for others who don't maintain their vehicles, a sealed trans is probably a good thing.

I'm even contemplating trying to dig up a manaul transmission version of the same car if I lemon this one....I like it that much, but from what I'm hearing about noisy clutches, mushy pedals and vibration issues, I'm not sure the IS will be my next car even w/ the MT.

Thanks again for the info though. You've been really helpful.

Sean

maxnix

"Cooler" indeed! Probably more of a heat exchanger to aid torque converter lock up at low temperatures at startup. ATF is ideally @176° F, so thiAs arrangement guarantees overheated ATF after intial warm up, ehich means faster ATF degradation.

maxnix

Think about it this way, if old degraded fluid is good, why isn't the original fluid old and degraded? Simply put, fresh fluid that meets OEM specifications is best.

Fluid degrades with heat and condensation primarily, which leads to degradation of clutch materials and varnish build-up. When this happens, clutch packs start slipping and shift solenoids work harder and slower.

The current heat exchanger tank above the transmission should give owners some pause. I bet a new transmission alone without labor is about $5K. What's its life? Maybe 100K -140K depending on owner's tolerance of performance degradation. OEM considers 100K lifetime service.

Since many drivers are renters and not owners, long life after warranty is even a lesser concern for OEM.

maxnix

Like the diagram says, "ATF warmer", not cooler.

Removing the warmer and hooking up a true external ATF cooler may be feasible if there is inlet and outlet plumbing for the ATF.

As most engines run at 210° F, don't know how that would "cool" ATF to desired 176° F.