Ken, I remember you wrote re. checking the fluid level of a stone-cold tranny on the notch above the plastic tip. Have you looked where it reads using that method in our current cold weather?

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I've been thinking... of course that's a dangerous thing.
Here goes anyway.

My guess is that when it's warmed up - as warm as it's going to get given whatever the current weather season - the level should be somewhere between the high mark for "partially warm" and the high mark for "hot". I know this goes against the Volvo recommendation and also goes against all your careful work reading temps off the tranny fluid pan.

Of course, working this way, when the season changes you need to recheck the level - since the final warmed up temperature will now be higher or lower, and the resulting warmed up fluid level will change. You would again want to verify it is within the marked ranges.

Hmmm??

The spec-writers know the fluid expands when hot and contracts when cold. So they establish a range of fluid quantity to maintain, using ambient temperature, and then mark the stick to show what those quantities look like when partially warm and fully hot. I suspect it's typically Swedish-German over-engineered. Not to knock overengineering. I suspect overengineering is why these 20-year old cars are still running.

The manual gives a quantity of tranny fluid for the system. I think it's 7.8 qt? My point is that it says nothing about temperature in that spec, and even so is quite precise.

Bear in mind, the levels marked on the stick should be sufficient to run the tranny safely at any temperature between sub-zero and ambient 105 or 110 deg. F. Maybe hotter than that.

I think the tranny's actual fluid requirements are
1) Enough fluid to enable cooling and
2) Enough fluid to enable circulation to all parts of transmission

I would guess that for circulation, as long as the fluid is up to the level of the tranny's internal pump pickup, such that it can operate and not deplete it's own lubricant source when distributing fluid through the tranny, that's the level it needs. Of course a level that's too high causes foaming and you must avoid that. So you don't let it go higher than the high mark for a hot engine.

Personally I wouldn't drive around with the fluid level low on the stick. I think you'd be risking insufficient fluid when cold.

Am I nuts or does this make sense?
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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors, quad horns. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.