It's normally very mild here in Ireland. We don't get extreme low temperatures like you guys do.
Most of us SVXers have extra tranny coolers in the system to keep the oil from burning up in Summertime. The majority of us with extra coolers have them working along with the OEM radiator one.
I would suspect that most of us use coolers rated 19000 lbs or over, for a car that weighs about 3500, or 4000 lbs laden. In really cold weather, the cooling capability we have put in is too good. It will not allow the ATF oil to reach optimum temperature, hence no 4th gear.
My suggestion is to put some aluminium baking foil in front of the aux cooler, to stop the really cold ambient air from over-cooling the oil. Covering half of the area, or a little more, would be about right.
Remember to take it off again when the weather warms up.
Joe
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