Wrong Transmission Fluid 100,000 Miles ago

[Qwoo8]

About 5-6 years ago when our 2007 Toyota Yaris was at about 100k to 120k miles I changed the Transmission fluid. I went to the local Toyota Dealership and they gave me Toyota Automatic Type IV Transmission Fluid and I did a drain and fill.

We later bought a 2006 Toyota Matrix with 60K miles since my wife converted me to these types of Toyota's (Same Oil, same filter, awesome mileage and engines). Now the Matrix is at about 115k miles and I changed the Transmission Fluid with the Type IV Fluid as stated in the manual. I bought 6 quarts + I had about a 1/2 a quart from the change years ago. I then pulled open my manual and see that the matrix takes the Type WS and that they aren't compatible. The Yaris is at 220K miles and is still running great (Did do water pump, thermostat, coolant a few months ago). I just ordered type WS I don't notice any shifting issues but the fluid is darker and looks ready to change.

Im really annoyed that the dealership service/parts employee gave me the wrong fluid years ago but I haven't had a catistrophic failure. Im thinking change the fluid and then maybe do it again to keep it fresher. I guess I could have a flush but it does have more miles. Would it be terrible to drop the pan and change the strainer. I hear that they don't always fit properly.

What are your thoughts? I really like my Yaris and want it to go for long long miles I hope this won't keep it from fulfilling its potential.

[tmontague]

I'd recommend you flush it with the proper spec'd fluid. Use the transmissions cooler hoses to perform your own flush, this ensures all old fluid gets out and is replaced with new

[Qwoo8]

Thats a really good idea I will need to locate that line. I should have ordered a couple more quarts of fluid.

[Brighton]

I mean, you accidentally proved it doesn't make a ton of difference to use different fluid. While yes it's good to stick with the OEM spec stuff, it obviously didn't kill the trans to use the not rated stuff, so I'd say no harm no foul.

[Qwoo8]

I think thats why I really like these cars. :headbang: I checked the fluid and it is darker then I like so I will be changing it when I get the fluid in on Friday.

[B.B._07]

The U340E auto transmission in the Yaris predates the introduction of Toyota WS ATF and it was originally intended to be run on Type IV ATF. The shift to WS ATF in 2002 was mainly based on the desire for a thinner ATF to boost fuel economy and to have a universal ATF to use across the product line. So really it's not surprising your transmission ran fine on the fluid it was originally intended to use.

[Qwoo8]

Thanks for your knowledge B.B._07 you have soothed my soul! :bow:

[06YarisRS]

The U340E auto transmission in the Yaris predates the introduction of Toyota WS ATF and it was originally intended to be run on Type IV ATF. The shift to WS ATF in 2002 was mainly based on the desire for a thinner ATF to boost fuel economy and to have a universal ATF to use across the product line. So really it's not surprising your transmission ran fine on the fluid it was originally intended to use.

Very interesting. I wonder if type 4 would actually be better for our transmissions when considering durability/longevity vs fuel economy. I also wonder if Type 4, being a more viscous fluid, would provide better clutch pack grabbing and holding in a turbocharged application like mine.

Qwoo8, I'm guessing you never noticed any shifting anomalies when you did the initial drain and fill with the Type 4?

[jansen.fan]

Qwoo8 was the transmission fluid change on your Yaris at 100k miles the first one you did on the vehicle?

I have a 2008 Yaris with automatic transmission. It has 160k KM (100k miles) and I've never changed the transmission fluid. I've read about issues with changing fluids late (Toyota recommends 96K KM) causing slipping in the transmission and I just want to avoid that. Thanks!