Idemitsu is OE on the Asian transmissions.

Just starting to appear on aftermarket.

https://www.idemitsulubricants.com/

BG located in Wichita, now Eldorado, KS. Been around a long time. Used to be very involved in racing and were big supporters of the SCCA events. May still be. I've never heard anything bad about the company or its products in the 40 years I've lived here. My 2 cents.

I'm going to play conservative this time around. I'll heed advice above and I'll stick w/ Toyota ATF WS for transmission since the manual is pretty specific.

Maybe I'll try BG oils for differentials and transfer case and power steering since the manual allows for generic fluids.

As a formulator of axle lubricants, I again recommend OE products. The Toyota axle lubricant is well-sorted out, and they are very conservative. The OE fluid is made by a very respectable Japanese oil company. There are many "service fill" axle lubricants out there, and many are very high quality. Axle seals are not something that you want to compromise with a lubricant that has not been approved by the OEM.

Of particular importance is when the service fill lubricant is formulated to work as a limited slip capable fluid, even if your axle is not limited slip. I don't know if your axle is limited slip or not, but you can induce noise, vibration, and harshness (NVH) with the wrong lubricant. Toyota is VERY conservative and does not make lubricant decisions without years of development and testing.

quote:

Of particular importance is when the service fill lubricant is formulated to work as a limited slip capable fluid, even if your axle is not limited slip. I don't know if your axle is limited slip or not, but you can induce noise, vibration, and harshness (NVH) with the wrong lubricant. Toyota is VERY conservative and does not make lubricant decisions without years of development and testing.

I agree with this completely. However, I am ignorant on on this topic (well, not just this) and while I'm sure Toyota used the best oil for the job at the time, it's been 10 years since the car was made. My uncertainty is whether or not a new fluid since 2008 is now available (ie - BG?) which would be better than the original factory fluids.

But then again, if product improvements could be made to factory fluids, I'm sure they would be made available (same ATF WS fluid name but perhaps improved formulation inside).

I'm not sure about the front/rear differentials (I'm not technical) but I think the Torsen center diff is limited slip.

In any case, I guess I can't go wrong with factory fluids. I tend to be risk averse anyway.

Thanks for the advice.