Thanks for the insight. IIRC the oil temperature sensor in my car is right before the oil filter. So I don't know if that counts as "sump" but it's probably pretty close!
Also for everyone arguing, I've run Rotella T6 0w40 in my other track car for a season and the UOAs come back pristine. I keep thinking "Surely this past weekend pushed it over the limit" and Blackstone will come back with something like "looks good, try it for another 6 track days!"
Thanks for the insight and for validating that thicker oils can raise temps. I agree that going thin for power is sacrificing a lot of risk/reliability for minimal gain. I remember in NASCAR they used to use special thin qualifying oil and put in thick stuff for the race.
Thank you for analyzing this more deeply.
I decided to go with Shell Rotella T6 5w40 and I will report back what, if any, temp rise I see at the track. Yesterday I was seeing mid-250s on Amsoil 0w20 (with some Rotella make-up oil) which I was comfortable with at the time, though not so much...
So I track my car and I notice that (very generally, due to different atmospheric, tire, and overall conditions never being the exact same two sessions in a row, much less two different days separated by weeks), when I run a thicker oil, my oil temps are higher. Which begs the question, is...
I just wanted to ask why you don't like Shell Rotella? I'm assuming you mean T6. I use it in my track car (a mostly stock Toyota 86) and it's an absolutely fantastic oil. A lot of the Porsche and BMW guys use it. I've done tons of UOA and it comes through shining every time...even after repeated...
You start with that (add as much fluid as you took out) as the baseline calculation. To be honest you'd probably be fine if you left it, but your trans should have an alternate way of checking the fluid level, such as at the fill hole or an overflow plug, and that's the correct way to fill it...
I think if the torque converter is literally designed to be drained that it's OK to drain it and the pan, then refill the pan with the same amount of fluid, and fire it up.
Today I took my car to the shop and had the transmission completely flushed with fluid I brought using a BG trans flush machine.
It worked like this:
Hook up machine to trans cooling circuit. Simply patch in to the flow, so the cooler gets flushed out, too.
Put machine on bypass mode and...
Thanks man, I'm really hoping no damage to trans. I was really worried, and the level was fine (even the fluid didn't smell super burnt), and I flushed it completely with MaxLife for now because that's what I could get 4 gallons of at a reasonable price on short notice.
Since then I've taken...
Believe it or not, this car does not have a traditional "transmission fluid passes through a heat exchanger in the radiator" system, there's a tiny sandwich cooler (which is just as much of a heater) bolted to the inside of the transmission tunnel.
So I'll be adding an external ATF cooler in...
Thanks guys, I should have been clear, a trans cooler is definitely in my future.
Since I needed to get this fluid swapped out ASAP and I saw a lot of good things about Valvoline Maxlife Synthetic Multi-Vehicle and I could source a few gallons of that same day, I'm going to flush with that...
So I know the first question you guys are going to ask and that's why race an auto trans? The answer is because I originally bought it as a daily driver and my right shoulder is arthritic, so the paddle shifters come in handy.
Now on to the problem: I just hit 36k miles and about 15 track days...