Ok. I've had 2 days with Sub 40° F mornings to see how the Red Line MT-90 GL-4 Transmission oil would work in colder temps and the 2nd gear "crunch."
Each time, I started the car and let it sit for 5 minutes, letting the engine warm up (which, in case you do not realize,
does not warm up the transmission oil) before starting to drive. Pulled down our road in 1st for about 100 yards before turning onto the major street. Pulled out and took 1st gear to 3K rpms and shifted to 2nd. I was immediately thrilled that I was not locked out of 2nd gear, like I had been with the Subaru GL-5 80W90.
There was a slight catch going in to 2nd, but not like it had previously been. On the first ride, I continued on and and as the transmission oil warmed, all shifts between gears leveled out and were nice and smooth. On the second ride, when I would shift from 1st to 2nd, I tried something different.
Clutch in, pull out of 1st and let the shifter go to neutral (if you let go of the shifter and let it sit in Neutral on it's own, it sits in the spot between 3rd and 4th gears), then pulled it back over and down into 2nd. This is all a fairly quick motion and it seems to eliminate the little "catch' I felt on the first day of cold driving. I had tried double clutching when I had the Subaru GL-5 in, and it helped, but still had the "crunch" and the lock out a couple times.
Seeing as numerous people have had similar results as mine by changing the transmission oil with pretty much every brand out there, but not totally eliminating the 2nd gear "crunch," my recommendations would be as follows.
If you have the 2nd gear "crunch":
• Change out your transmission oil (Highly recommend a GL-4 oil).
• Take it easy when you start driving and let the transmission oil warm up.
• When cold, Double Clutch going from 1st to 2nd (or try my suggestion for drifting into Neutral).
For those living in colder climates, it might be worth trying an oil pan heating element:
https://www.amazon.com/Kats-24150-Wa...2394558&sr=8-8
Be nice to get some input from anyone who is using one or willing to try one out. For $35, I may just get one to see if it makes any difference on the car. I'll report back if I go that route, but as we have relatively mild winters in the Mid-Atlantic of the USA, that money may go towards something more necessary - like a ceramic coating.
Once my BRZ was warmed up, I haven't had any issues with the transmission gears.
Hope this helps shed a little light on this and I do hope that you all enjoy your BRZs as much as I am!!