Group:
Just tried to buy Mobil 1 trans fluid at Napa, but they want to knoe if it takes the Mercon type or Dexron type. I suggested to them that I thought those two were interchangeable, but they disagreed. They suggest I get oil from Volvo! That will be real expensive I think.

They had Castrol Syntec on the shelf, but I had secified Mobil 1.
Any difference?
What type do I really need?
S90 with 72 k.
Thanks,
S'V'

What's the deal with the occasional advice that synth ATF will damage seals/gaskets, etc? This seems especially true with regard to high milage. Seems I have seen posts to this affect and recently got the same *advice* from a local indy volvo mechanic. Yet here on the board the overwhleming advice seems to be synth ATF is the way to go. Thoughts?

(if there is a prior post that covers this please direct me to it)

patwa

Mobil 1 synthetic ATF does not work on Mercon V tranny fluid. This is a new version of Mercon and not in our cars. That might be the confusion, Volvo specs Mercon III, which Mobil 1 ATF is good for. Some of the very new Volvos might take this new specification but the 960/S90 do not.

Yes, these trannies love M1 ATF. I'm using it two AW30-40 trannies and have for years.

DEWFPO
--
1998 S90 071,245 and 1995 964 154,100

You were right they were wrong. Go to them with this print out.
Owner's manual fluid specifications.
Both dextron 3 and mercon 3 can be used. I have Mobil 1 ATF in my 960. It works great in this car.

Go for the Mobil 1 full syn, it meets both the Dex III and Mercon specs. Info at the Mobil website.
--
Gary Gilliam Sumerduck VA, '94 940 na Regina 150k, '86 240 180k

Thanks to all of you. I did not have the car or book today and will not have it for another week. In the meantine I can order some Mobil 1.
Napa just lost a sale. I will go elsewhere.

S'V'

Dude, you should be happy that they erred on the side of caution rather than giving you a fluid that they said " oh sure it should work," and then when you blow your transmission saying, "bummer!"
I would take the printout like the other poster said and then they might learn something for the future. However most trans fluids say both dextron and mercon right on the front!