Hi mk000000000000000000000000000000000000000000000000000001,

As far as the trans goes, I highly recommend Mobil1 ATF. It has served me very well in 2 of these AW30-40 transmissions. I also recommend using the home flush procedure documented on this site. Some prefer to drop the pan, clean it and change the internal filter, others don't... your choice.

The flame trap is located at the downward elbow of the intake tube just before it goes into the throttle body. The trap is T'd into the intake tube, faces rearward and is ~1.25" in diameter. It has an ~3/4 inch dia. hose coming out of it and diving down between the intake tubes. Twist it 1/4 turn and remove it. It is/was a white disk with many holes. Just make sure they are clean and clear. That's it, just reinstall.

Check al those vacuum hoses as Poolman suggests. Those rubber elbows disintegrate by themselves as well as the O ring between the vacuum tree and the intake manifold ball.

I have found that the thermostat's last about 5 years or 100k miles or so. They fail open so it's not catastrophic..... but their $14 at the dealer and only take 2 bolts removal to replace it so it's good maintenance.

Volvo recommends replacing the brake fluid every 2 years. I bought a Motive Power pressure bleeder, it makes the job easy and foolproof. Cost about $39 on the web.

Hope this helps.

DEWFPO

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1998 S90 077,400 and 1995 964 154,100