Transaxle fluid

I hope it stays that way.

 

Just out of curiosity, why are you convinced that WS isn't needed? If I understand things correctly, MG1 and MG2 are also bathed in the WS ATF fluid. I'd be concerned about the windings being chemically affected by incompatible lubricants. Is my understanding correct?

 

PC member Edthefox has done similar, using redline I recall. He offered to obtain a chemical analysis of that fluid later on, which could certainly help narrow the uncertainties here.

 

Why don't you just use Walmarts brand that is WS certified?

 

The WS is now required in Toyota automatic transmissions. I doubt there are any special electrical properties to the oil, but with a conventional automatic transmission there may be an additive package needed to prevent slip or shudder

Like with Chrysler automatics requiring ATF +4

 

I've been using Redline D6 for 9,000 miles, no problems.

 

Hi Tochat,
Yes still running on Redline D6. I changed it at 5K but present mileage is 28K so I am waiting till I get at least 25,000 miles on that oil for a fair test. Running really good so far. Very smooth. Will probably change the Transaxle oil every 30K after that.


I will pull that Redline at 30,000 miles. I saved a sample of the original WS 5K pull also. And will have 10,000 miles on a Mobil One 10-30 sample by then too so planning on doing them all the same time.

Lifetime average of 45/46 mpg.

 

I agree with you for the most part. I don't believe there's anything special about the trans in this car MG's aside other than its a very well engineered planetary gear platform. Extremely well engineered.

I think I may have been one of the first here to use something other than WS in the trans other then Bob Wilson. Lots of posters here posted saying I was going to blow my trans up 'cause there's no dielectric compund in my new crazy fluid. Its going to short out the windings.

Nope.....

BTW, I never could figure out why no one said to Bob he was going to blow up his trans when he went with Amsoil. Amsoil is excellent also except it attacked copper. High sulphur content. The Gen I had open bearing races. Gen II's are sealed. Amsoil would probably be excellent also in the Gen II's.

Anyway your last post proves my point again. How could there be any dielectric compound in the WS if its dirty with gear wear?
Many many posters here report WS fluid black when they changed at excessive miles.

The darker the fluid the more metal in solution until it becomes a highly conductive compound. Obviously negating any dielectric claim. Which still continues to this day.

How dark was your fluid?

My contention has been this trans requires nothing more than a GL-4 quality oil to survive. My opinion is Redline makes the best GL-4 lubricant available. To me the trans ran better after a change to Redline. It was quieter. Especially at the few times I've gone 90 miles an hour. Effortlessly. Redline makes oil also but I like Mobil One. I use that. I intend to keep this car at least 6 years.


I never advocated anyone change to anything other than WS.
Just reporting my findings and opinion.

But the peeps be freakin'.

WS fluid is an excellent product but I think the after market high end lube is better. My opinion only. Please don't post saying I'm not going to change to Redline. I don't care.

But good luck to you Magruder. I would dump that fluid again at 5K just to get all that oil wear oil out of there. I am on a 30K interval myself.

 

Let us know if the winding insulation ever fails and you have to replace the transmission. If you ever try to sell the car be certain to tell prospective buyers about your experiment.

 

Amsoil, Redline, Supertech, all have oil that is WS rated. It isn't a Toyota scam, they don't make oil, do they? It is a question of friction I believe, and getting more mpg's, as WS is a low viscosity atf. I would like to know where USA Toyota buys their WS. I have a suspicion it is from Warren, who makes excellent oil under their Mag1 brand. That's who makes Supertech WS rated D6. Maybe they have a special contract with a major oil company, but I haven't seen a Mobil, etc, WS rated yet, only D6. I am changing mine soon, am thinking Redline or Amsoil as I trust their names to believe their WS spec claims. They are also synthetic, not sure about the Toyota black bottle WS or Supertech D6. I wouldn't play a guessing game with a transmission, use only the specified.

 

Given that there doesn't seem to be any significant problems with WS other than the price (but how often do you need it?), I stuck with the official WS fluid when I changed my transaxle fluid.

 

1) There is one thing special about the trans in this car - unlike traditional transmissions, there are places within the transmission that could easily have electric fields of 500,000 Volts per meter. These are associated with MG1 and MG2 within the HSD transmission.

2) It's not an issue of the oil having a "dielectric compound." The transmission fluid needs to have a high enough dielectric breakdown voltage so that it can't arc over when subjected to the electrical stresses due to the voltages across the windings of MG1 and MG2.

Using a fluid that does not spec its dielectric breakdown capability constitutes a risk that it could break down. It could break down not only when it's new, but when it's used and has some microscopic pieces of metal floating around in it.

You took a gamble and (so far) have won. Congrats! Good for you! (and I mean that most sincerely). But, don't kid yourself and think that you didn't take any risk.

 

This is true of almost all new modern electronically controlled automatic transmissions. Note, the Prius is more like a stick shift with a power transfer chain, it does NOT have a torque converter or shift clutches

The Heavy Duty Allison automatics have very specific warnings about preheating, generally when the ambient temps are <-20 F. Allison specifically warns that transmission operation can be sluggish, and fail altogether, in bitter winter temps if appropriate precautions are not taken

It's one thing to expect the owner/operator of a medium duty truck to heed the warnings and service the thing on schedule, but it's unlikely to expect the average consumer to do so

I have experience with industrial oil filled transformers. The fluid used is specifically tested for dielectric strength. I see nothing about WS or any other ATF being tested for dielectric strength

Think about the composition of ATF: as WS is also used in Toyota automatic transmissions, such as the 5 speed auto in my FJ Cruiser, it has to have friction modifiers so you won't experience torque converter shudder, slipping, or harsh shifting

As far as that goes, why not use this product in the Prius cvt:

Mobil Delvac Synthetic Transmission Fluid 50

The Delvac 50 does NOT contain friction modifiers, as it is specifically intended to operate with heavy duty synchronizers