Best trans fluid for a hi-miles ST300?

[Special_Deluxe]

Hello,

Have a '68 Special, nearly 270,000 miles. The original ST300 is still in the car and still works great. Have always used Castrol Dex3 for topping up when needed.

Question: Can't seem to find Castrol Dex3 anymore, now it's "Multi Vehicle ATF" or something similar. Is this the same formula as the old Dexron3, with a different name? Someone said it was due to licencing issues and the formula is exactly the same. Is this true, anyone know? Or is it a "mix and match" type like the old One Type Fits All stuff they used to sell at Kmart?

Much thanks for any help.

-Mike

[SFC ROCK]

try going to castrol oil.com there is a bunch of info there about their products

[Special_Deluxe]

My thanks for the response. Have looked around the Castrol site but there's not really much there in terms of fluid compatibility, old vs new. They say it "meets specifications" but I'm not sure that means it'll mix with the Dexron that's already in there. And given the 270000 miles on my trans a tranny fluid change at this point is a no-no.

Hoping to hear from folks who have topped off with the new multi-vehicle ATF and did they have any problems afterwards. (Surely I'm not the only GM guy left in the world with a leaky transmission! ) Did the company change the formula? Or just change the name? Being the old-school type that I am I wish they'd just leave things alone

My thanks again for any help.

-Mike

[Renshai]

I just did a fluid top off on my 66 225, which I believe has a st300 in it as well...didn't even think about it and threw in Mobil 1 tranny fluid and it works like a dream...no problems thus far, but it is a 52,000 mile original too

[Special_Deluxe]

Update: Have been topping off with the new "Domestic Multi-Vehicle ATF" (Castrol) for the past month or so and it seems to be blending okay with the Dex 3 that's already in there. Was thinking about a flush n' fill, but with 270000 some-odd miles on an original tranny IMO it might cause more problems than it solved.

So far, so good.....keepin' them fingers crossed