I have 2 questions regarding a Toyota Corolla with 146,000 miles.

1. I've heard that a tranny flush on a high mileage vehicle can cause problems with dislodged material. Is it risky to just drop the pan (or drain if there's a plug) and top off the fluid? Does that adequately refresh the fluid? Right now I don't have synthetic, but would like to go there - is it ok to mix synthetic with the non-synthetic that's already there?

2. Regarding the power steering fluid - same question about mixing non-synthetic with synthetic.

The specs on my Corolla say Dexron II for both the tranny and power steering.

Thanks!

txgreasemonkey

I would not do a transmission flush, where a solvent is used. Synthetic ATF (e.g., Mobil 1 Multi-Vehicle Synthetic ATF and Amsoil Universal Synthetic ATF) is completely compatible with conventional ATF. Change the fluid when it's hot and dropping and cleaning the pan should be fine. I know you will be happy using it in your transmission and power steering unit. I run nothing but synthetics in my engine, transmission, and power steering on my 2000 Taurus. In my 1993 Civic, I run synthetics in the engine and transmission; however, in the power steering unit I use Honda Power Steering Fluid, which is a partial synthetic.

fripco

Wow - that was fast! Thanks for the good answer...

Here's another one - Is there any truth to the rumor that Amsoil motor oil can cause seal leaks in a high mileage engine? What's the risk there?

txgreasemonkey

Amsoil makes superb products. Their synthetic products are no more likely to cause problems than anybody elses. The natural higher detergency of synthetics will clean engines, transmissions, and power steering units more than conventional lubricants. I have never known anybody to develop seal leaks from using synthetics. It's especially unlikely with the EPDM seal materials used today. This was an objection heard 25 years ago and the formulations today are compounded to not cause seal swell. Once you start using synthetics, you will never turn back.