Is there any substitutes or differnt ATF i can put in a 91 940t automatic than the standard Dexron IID it calls for? Ive heard that mixing is real bad, and ive also read that anything newer than Dexron IID is fine. I need to fill it up before tomorrow and its on min. How much Should i add if its right on the Min line when running on the 190* side. Thanks.

 

I've always wanted to put some merconV in mine, but really the dexIII is a step "up" from the dexII it calls for, especially considering you can't even buy dexII anymore. They haven't made it for about 10 years. Go with the dex/mercIII, and if you want to upgrade then go with a good synthetic dex/mercIII, or a good universal synthetic atf.

 

The Volvo owners manual says to change the tranny fluid every 20K. (I've often wondered how many people actually do this - particularly since their odometers probably don't work.) Using the drain plug (one of Volvo's good ideas) you can drain around 3 quarts each time. Each time I do this I've been replacing the Dexron with Royal Purple synthetic. Expensive as hell, but I figure I've spent more money on dumber things. Of course, you have other options: Dexron 6 would work; so would cheaper synthetics, like Mobil 1. Automatic trannys are one of those things where you pay now, or pay later. I'd rather do the changes than the overhaul.

On my 740, which has an AW 71, it usually takes about a quart between Min and Max, but I always add only a half quart and then run it for a day before rechecking, just to be sure I don't accidentally overfill..

 

So i could empty the drain plug, and add a synthetic to it, about 3 quarts and be fine? And then every 20k add more? Or should i do that rotation 4 times right away trhough all gears and change it out so everythings synthetic/

 

Quote:

Originally Posted by schwalbe181

So i could empty the drain plug, and add a synthetic to it, about 3 quarts and be fine? And then every 20k add more? Or should i do that rotation 4 times right away trhough all gears and change it out so everythings synthetic/

Yeah, basically every 20K you're draining and adding 3 quarts, give or take; unless you've got a major leak 3 quarts should put you somewhere above the MIN line. The tranny holds something like 7 or 8 quarts - I forget the exact amount, but it's in the book - so you're not doing a complete change. The rest gets trapped in the torque converter and various other places. You could do a flush and get it all at once, but I don't see the need. If you keep using synthetic every time you change, eventually that will be all you've got.

I'm a big believer in synthetics, but only if I'm not dealing with a leaker - that stuff is too pricey otherwise. Royal Purple tranny fluid is like 13 bucks a quart and even the Mobil 1 is 6 or 7. You don't consume tranny flluid, so if you're having to add more than a half quart between changes you've got a big enough leak that you need to take care of that first.

 

I used to compromise on the changing thing by dropping the 2.2 litres or so out that came when the transmission sump was drained, replacing it and then driving for a day or so, then repeating the task twice more. This kept an AW71 in capable condition for 250,000 miles. They are wonderfully well built and tough transmissions, but I have done the some thing to a more fragile ZP4HP22 and I am at 150K with no discernable deterioration from the 90K when I bought it.
Recently I was somewhat broke and I bought some cheaper Dexron and I used to top up my power steering and that was a mistake, as it went very grindy and noisy. Whilst it cleaned the system (the racks seem to stiffen with age, especially when the fluid is cold-presumably its the piston seals in the rack) I had to get rid of it quick and flushed it out. Like the other guy said, buy good stuff and it will not let you down.

 

I did the changing thing every 25K, which is more or less what Volvo recommend.

 

If you use a good quality synthetic and ensure a complete change, you can comfortably double drain intervals on an auto trans. The synthetic fluid really resists oxidisation very well.
Combine it with a nice big external cooler and the thing will last a very long time.
Having said that, an AW box costs like $500 to rebuild so don't get too upset if you miss a change every now and then!