Change transmission oil on my '02?

Interesting.

I'm not sure putting engine oil in the transaxle is a good idea. What is the rational?

 

if nothing happens in the box and the oil just splashes, then what is the problem, what prevents you from doing this?

 

For me personally, nothing prevents me from doing this, it is just Toyota specified a very specific transmission fluid and as that is readily available I just use that. It never crossed my mind to use engine oil.

I'm more interested in why you're taking the approach you're taking.

 

For one thing, it splashes on the insulated electrical windings of high-voltage electric motors, and one goal of the prescribed oil is that it should not chemically degrade the insulation.

Even more generally, oils have always been chosen for very specific conditions of viscosity, lubricity, and so on, and I can't recall any instance where the oil for a car gearbox was specified to be the same oil used in the engine; I would be unlikely to assume either one would be suitable for the other use.

 

you're funny, I laughed. How is my Prius different from yours?

 

This is correct. You can't see the magnet unless you take the whole pan off of the transmission. At least for me, the magnet normally has a little bit of "fuzz" on it, as stated.

For OP, or anyone else contemplating a transmission fluid change, you can get 6-packs of Toyota T-IV ATF on Amazon for roughly $50, delivered, in the US. At least for me, this is a lot better than I can do at the local dealer.

I also recently discovered that the Dorman 095-149 aluminum crush washer is pretty much an exact replacement for the Toyota 90430-A0003 washer, used on the transmission drain and fill plugs. A bit over $2 and on the shelf at an O'Reilly near you.

I very vaguely recall that some 70s Japanese cars (Datsun?) took engine oil - like, 10W40 - in their manual gearbox, but I don't know if 1) that's true or 2) it was a factory spec, or some kind of hot-rodder/enthusiast/lore thing. In that era I would have expected something more like 80 or 90 weight gear oil.

 

From 1990 Honda Accord Shop Manual:

engine oil: 10W30 or 5W30
manual transmission: 10W30 or 10W40

80~90 weight gear oil was specd for something on our daughters previous 4WD Honda Pilot. Not the rear differential (which took a proprietary Honda fluid); it was another 4WD related component in the engine bay, transfer case or similar?

 

My manual states to have transmission fluid changed at 75K. The dealership stated that was not accurate and so at 55k i paid for the transmission fluid change. I still think I should have waited until 75K, but whats done is done. My 2001 prius now has 91K and I am thinking now to have it redone at this point, even if dealership insists I do.

 

yes that is interesting. Hmmm. Maybe in that year they either improved the system or realized it was not necessary to change at 75K. I think I will wait 10-15 K or more before I have it serviced again. No sense wasting money. Thank you for responding.