The automatic transmission fluid was low on my 1991 Volvo 240 Wagon, and I should find out why. Regardless of the cause, I needed to top it up.

I did so with the engine running and warm, and after shifting into each gear for a few seconds. I used the tube with the yellow-handle dipstick near the firewall, and tested the level again. Yep, too low.

Into the tube, I inserted a small funnel that I’d bought for this reason. I made sure that the funnel was clean, and I avoided cleaning it with cloth that might leave lint that might contaminate the transmission oil. I wasn’t too happy about my chances of not spilling so into that small funnel I put a larger funnel, and into that I poured the fresh automatic transmission fluid.

I would prefer to read the official Volvo opinion as to what type of ATF I should use, and I don’t recall reading that recently or at all, so hearsay and common sense are my fall-backs. On those premises, I used Dexron/Mercon III.

It’s easy to overfill, so it’s good to pour in some fluid, check the level, then pour some more. It’s easy to pour more in a royal pain to take some out if you’ve overfilled the transmission.