I posted this on the s/v90 forum as a response to another thread, but that forum looks like a road less travelled...

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 - I've looked, but haven't found anything conclusive).

patwa

I believe the OEM fluid is synthetic. How else could they recommend no change schedule in the owner's manual?
--
'96 965, 16' wheels, rear 18mm bar & Koni + 204HP cams at 124K. Had '85 745 Turbo Diesel for 200K.

QUOTE: "How else could they recommend no change schedule in the owner's manual?"

1) Complete lack of a concience.

2) A desire to market to a segment of the population who is catagorically opposed to maintaining a vehicle. ("Just drive it and forget it! Then trade it in at 100K miles")

In my humble opinion.

Jeff Pierce
--
'93 945 Turbo ( one kickass family car ! ), '92 Mercedes 190E (my daily driver), '53 Willys-Overland Pickup (my snow-plow truck/conversation piece -- sold to a loving home), '85 Jeep CJ-7 w/ Fisher plow

The OEM fluid is not synthetic. That's why it is a very good (excellent) reason to change it.

I have never seen a seal, gasket or tranny damaged from using synthetic ATF (as long as it was the correct spec fluid for that tranny) and I have been using the stuff is all my vehicles for many, many years. I have always used M1.

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

It kind of makes you wonder how these rumors get started, doesn't it? I suspect it is a funcion of the Brickboard itself. For all it's good, we have a tendency to draw wildly (that may be a little strong) inaccurate conclusions from a sample of one or two cars. Who can forget the angst we shared with Tom Irwin? We've been done this road before, but by it's very nature, this forum has a very skewed population of cars, and conclusions we draw tend to perseverate.

Oh yes, use synthetic fluids, period. I'm not sure that you then need to change the fluid every 30K as you would one with dino fluid in it. The specs are pretty impressive on synthetics. I would change it every 50 or 60K, unless you haul wood in an oversized trailer for a living.

--
John Shatzer, '97 V90 @ 115K

I have never seen any evidence that syn tranny fluid will damage seals/gaskets etc. I have seen higher mileage vehicles start to leak from switching to 'synthetic'motor oils. If that is the case, then the gasket or seal was bad,and the oil just cleaned out the hardened cr@p encrusting the seal and it would have leaked sooner or later. I put synthetic in quotes earlier because the line between conventional and synthetic oils has become very blurred. Is a group III oil synthetic, or only group IV or V? The new Pennzoil multi-vehicle trans fluid( and other companies now have the same thing)is a synthetic blend. I just bought a case of it to make it easier by not having to stock both the Dexron III and Mercon V fluids to service my fleet.
--
Gary Gilliam Sumerduck VA, '94 940 na Regina 150k, '86 240 180k