we brought one of our dozers in the shop for winter time service, it had been outside all season. Anywheres from 10F degrees to 30F outside, in the heated shop overnight the left hand side final lost 3 gallons of 80-90. Never had a leak on it before, refilled it, been a day and has not lost anything. Dozers is a fiat allis 21c, oil sampled finals before service, no sign of any issues with metals. Seems alittle odd this happened when we changed the temperatures, anyone seen something like this before?
I've had it happen up here in this cold a time or two, but not to the extent your talking. Not more than a quart or so came out and then healed itself up with no more issue's. Gremlins maybe.
Most likely the case and seals expanded from the warmth faster than the ice cold innnards did. Perhaps the side that leaked was closer to your heat source.
I wonder if condensation could have caused ice to form making enough pressure to expand a seal? If it were me I would have done a fluid change once warmed up.
I had that happen last winter on my D6c. Had worked in some mud not long before it got cold, but thought I'd gotten everything cleaned out. On a warm day I moved it about 100' into the machine shed and shut it down. When I walked around the back the final drive oil was pouring out of the inside sprocket seal. Figured some frozen mud had ripped out the seal. I pulled it down to replace it but found the seal was ok....the mud must have just forced it out of position enough to dump the oil. As it turns out I found some other problems so the effort wasn't wasted.