ATF temperature?

[fishbone]

Hope you guys don't mind me reviving this thread, I'd rather not just open a new one.
What is "too cold" as far as ATF?
I have a 5EAT Subaru Legacy GT and I have a TruCool 4452 cooler on it. Today for the first time I monitored the temps a bit and cruising at 32*F and some very easy driving from light to light with no traffic, the temps were around 53-55*C which is roughly 125-130*F. The manual usually refers to normal operating temp between 160-180, not sure if what I am seeing is too cold, to the point of being detrimental.
Transmission shifts fine, but if I get on it sometimes it feels like it rides the gears a bit instead of "biting" into them like during the summer. Figured this is expected since the ATF may be a bit more viscous at this time of the year. This seemed to have become more obvious once I switched from OEM to Amsoil ATF.

 

[mechtech2]

130F is not horribly cold.
but according to charts I have seen, being below optimal [about 175] will cause more wear on the transmission.
How much? It seems about 10-20%
I would not worry about it. I'm sure she'll get much hotter in certain circumstances.

 

[fishbone]

And here I was thinking you guys insensitive to my issue by not replying, only to realize I did not subscribe to the thread, so no notifications

Mechtech, what literature is indicating what you mentioned? I dunno what to say, this car is tuned so that 20% accelerated wear is a pile-on whatever is already going on.
I don't think anyone has done a VOA on the Subaru OEM ATF stuff to compare to the viscosity properties of Amsoil ATF. I will try to monitor temp when it is colder than 32* and see what happens.

 

[mechtech2]

http://performanceunlimited.com/documents/

Here's a start.
Nice charts.
Not razor sharp Gospel, but a very good general idea.

 

[fishbone]

I talked to my local transmission guy and he literally said the colder the better as long as the converter is locking up. He said as long as no slipping it's good to go and there is no extra wear. He is a product liability expert for the Co I work at and has been racing/building autos for longer than I've been alive.

 

[mechtech2]

Colder is better?
No.
There is a minimum temp that should be encouraged.

 

[rslifkin]

With ATF, I personally think that as long as it's warm enough for the transmission to enable all of its gears, TC lockup, etc, and shift normally, then it's not too cold. Condensation isn't much of an issue in transmissions, especially if you take longer trips, where even 120* is enough to cook off (over time) the very miniscule amount of water that may end up in the transmission.

 

[fishbone]

Yesterday was about 30*F and drove for a good 20 minutes on the highway, at the first stoplight I floored it from a full stop and it basically banged into the rev limiter from 1st to 2nd several times as if it was in manual mode and I have not upshifted. It rows through the gears at redline fine from 2nd up, more on the soft side, but 1st to 2nd is all sorts of iffy. I also kicked it from a roll and it acted as if it downshifted twice. It grabbed a lower gear then "slipped" into another yet lower gear before making up its mind. So I guess this serves as proof that it is possible to overcool a modern automatic. It otherwise shifts just fine at gentle throttle, it actually shifts nice on the firmer side. I don't think it takes much ATF temp to allow the torque converter to lock up, I drove for about 10 minutes in 15*F with almost no stops and it locked up. The transmission cooler is coming out weather permitting and we'll see what temps I hit this summer. The thing that beats me is that I have had none of these issues for two winters before I switched to Amsoil. This probably doesn't account for much but some auto Mini Cooper owners have reported similar issues on Amsoil, which prompted some to go back to stock ATF or switch to another synthetic. It's the reason I opted for Mobil 1 ATF for the Mini and it's working great in the winter.

 

[mechtech2]

http://performanceunlimited.com/documents/

Check out the trans temp charts. If not 100% Gospel, at least a good idea of what temps are OK.

 

[fishbone]

Thanks. I've read the link the first time you posted it