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hello, bricknuts!
can any of you walking volvo encyclopedias clear this up for me about coolant and atf mixing?
This was posted by rule 308 in the 900 forum, the original discussion is here: http://www.brickboard.com/RWD/index.htm?id=917496
Well, since the trans line pressure is much greater than the cooling system pressure, when the cooler fails it is usually a one-way valve and sends atf into the coolant. I have done a bunch of these on the old red engines and by the time it gets bad enough for your average chuckle-head driver to realize there is a problem it usually has eaten up a bunch of the rubber hoses…. As far as the transmissions every one I have seen has been on an old read engine so I have no idea how the aw3040 is going to take to that. But like I stated there should not be much coolant in the trans at all. If you have a good auxillary trans cooler I would not worry about by passing the factory one. If you ever cut the side tanks off of one and looked at the cooler you would realize that there is not a whole lot going on there in the first place. Flush the coolant, run it on simple green and water for a couple of hours (may even want to let it cool all the way down once before you drain it),flush the trans good and proper, and run it.
and here is a different viewpoint from fitzfitzgerald, the original discussion is here: http://www.brickboard.com/RWD/index.htm?id=926786&show_all=1
If the tranny fluid is pink (like a Pepto-Bismal milkshake) you probably have a leak between your cooling system and your tranny cooler. You should have two tranny coolers, an external one that's mounted between the AC Condenser and the Radiator, and a second tranny cooler that's mounted inside the radiator end-tank.
If engine coolant gets into the transmission, the Ethylene-Glycol in the coolant will disolve the clutch packs in your transmission (and start giving symptoms that you are experiencing). If this is the case, your transmission is not salvageable, unless you want to pay to have it rebuilt (which isn't cheap). I'd also change out the radiator, or your next tranny will suffer the same fate as the first.
(from a separate post)
http://www.brickboard.com/RWD/index.htm?id=929877
I would suspect that your transmission is still going to be in need of replacement in the near future, and I would strongly advise you to start shopping around the local salvage yards for a replacement one. The Aisin-Warner transmissions in our 200/700/900 Volvos are pretty bulletproof, but engine coolant will kill an automatic transmission. The Ethylene Glycol disolves the clutch packs and is not easily removed from the system. A typical American made transmission (Ford/GM/Chrysler) can fail in a quick as 2 weeks from the time of contamination with engine coolant. After reading almost a dozen or so accounts (in the last 2 years) of Brickboard members who have encountered this issue, it would seem that our Aisin-Warner transmission can go as long as 6 months to a year before failing (after contamination with engine coolant). Even though you've flushed the transmission ATF with fresh fluid, I would expect it to need replacement within a year from now (depending on contamination level, duration, and driving conditions).
the reason this is important to me is because my '89 240 with the red block engine and with original blackstone radiator had similar issues where there was reddish oil in the rad. expansion tank. (I think that's what killed my original tranny--car was driven for 15k-plus miles before the tranny went out.) at the time I didn’t think much of it until I did a coolant flush after I got a new tranny and still saw atf in the coolant resevoir, only then did I suspect some coolant/atf mixing issue. after reading about "catastrophic" cracking and the possibility of atf getting into the cooling system via the cooler lines, I got a new all-metal rad. installed. I got a new thermostat, uper and lower rad. hoses, and draining the cooling system (I don't think it was a flush in the sense that a garden hose was attached to it and water was ran through the system). my volvo indie said no need to flush atf (had it done about a month before by him). so, is he right and I shouldn't be concerned, as rule 308 says? I did an atf flush for a peace of mind though :o)
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