ATF Fluid drain and fill

Guys, all of the advice is awesome and it makes me feel a little more comfortable with doing a drain and fill. I will follow that up with dropping the pan the next time in 6 months or a year depending on the miles driven. I will definitely never do a "flush"!

Can anyone recommend the best fluid to use, brand, specs, etc?

 

Valvoline Full Synthetic MaxLife

 

Valvoline Maxlife is fine, but I noticed a slight drop in fuel economy in 5 different Toyotas from 2004 to 2009 models with close to or above 200k mi. I think Valvoline has a higher viscosity. It does work nicely though and improved the shifting on every one. Amsoil sells an OEM fluid or Signature Series for rich folk. I have never tried Idemitsu, but that would probably be good.

 

Interesting it would have an effect on fuel economy. How much of a difference did you notice and what were you using before?

 

All of the vehicles had original Toyota WS fluid that was dark and turned into varnish like old gasoline.
one Corolla was giving codes for the shift solenoids before the change. They all had hard shifting.

The first drain and fill replaces about 40% of the fluid and there was a 1 or 2 MPG reduction. At first I thought the transmission was slipping.
after driving them for months, I'm sure it wasn't slippage. One vehicle was a Prius with its weird CVT, that one is a 100% fluid change with 1 drain and fill.

 

First time I've heard this. It does not sound right to me.

OP, FWIW, I've been using Maxlife for several years in my truck with several drain & fills. I have never experienced any MPG drop as a result.

 

This is interesting though. I think I will do a milage comparison before and after. If I notice a difference I will report back. The only things I can think of that would cause this are, as stated slippage or the added resistance from the incorrect viscosity fluid.

 

Another hat in the ring for no discernable loss of mpg after several drain and fills with Valvoline MaxLife ATF (starting at 150k through 155k). And also the first time I have heard of that.

"40% on the first drain and fill" Math is gonna do a solid disagree with you on that one. It takes around 10 qts to fill the ATF system- most folks empty 2-2.5 qts on a drain and fill, or around ~22%, which is obviously not 40%. So unless you were doing something like running the vehicle and catching ATF from the return line while you poured new fluid in, 40% on a drain and fill for a 1st gen Tacoma is wildly inaccurate.

 

I'm sorry you disagree with the 40% assessment with a drain and fill. Most of the Toyota models (none of which were 1st gen Tacomas or stated as such in the post). in question here drained 3.4 qt. from drain plug; total capacity of system: 7.7 qt. My calculation is based upon 3.4 qt. / 7.7 qt. = 44% .

The mpg reductions that I witnessed seemed mysterious, but were confirmed with several mpg calculations to find an average. One of these vehicles experienced a further reduction in mpg after a subsequent drain and fill.

Perhaps your differing results may be due to your area's climate, driving habits etc. This information is given as a springboard for further curiosity about this. I will not be using maxlife because the mpg drop is not worth the initial cost savings of the fluid; 1 mpg difference could add up to hundreds in several months time.

To further substantiate the connection between fluid brand and mpg, Amsoil does advertise it's signature series fluid as "fuel efficient".

I want to know more about this, but I don't want to dedicate my life to it.