Benefits of increased transmission fluid capacity besides cooling?

doublespaces

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With the assumption of a high quality transmission fluid cooler, what is the reason for increasing the fluid capacity through a trans pan for example? If you have a good cooler, doesn't this just make your service intervals more expensive?
 

aus335iguy

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The volume of oil that contaminants are spread across is higher. Therefore the oil should stay in better condition for longer(not by much)... all depends on your perception of value.
 

dyezak

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Additional oil doesn't help cooling, it's a heat capacitor and will mean that it takes a bit more abuse before the fluid gets too hot but will not improve cooling at all.

I'm struggling to determine any benefits (true benefits) to additional capacity. We used to see this as a common thing to do on high performance builds on old V8 engines because we would move to high volume oil pumps along with increased engine RPM. Those two things combined would suck the factory 5qt oil pan(s) dry during sustained high rpm operation. So adding 2-3qt of engine oil was a real and true solution to a real problem.
 

doublespaces

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Additional oil doesn't help cooling, it's a heat capacitor and will mean that it takes a bit more abuse before the fluid gets too hot but will not improve cooling at all.

I'm struggling to determine any benefits (true benefits) to additional capacity. We used to see this as a common thing to do on high performance builds on old V8 engines because we would move to high volume oil pumps along with increased engine RPM. Those two things combined would suck the factory 5qt oil pan(s) dry during sustained high rpm operation. So adding 2-3qt of engine oil was a real and true solution to a real problem.

You're right, it doesn't cool the fluid itself by simply having more but it does raise the ceiling for sustained pulls and heat absorption, or heat 'capacitance' as you state. I mention it because it is a factor when considering upgrading a cooling system due to the larger 'cooled' reserve of fluid.

But outside the heat sink effect and the dilution of contaminants, I'm trying to figure out what other benefits it can bring.
 

Aaron

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I am trying not to think hard, but I added 2.5 quarts of engine oil capacity to an engine I built a while back. Engine had known documented problems with running the pan dry like dyezak mentioned. Another major advantage on this setup was a significant safety margin if I ran low on oil. Basically I could lose 2.5 quarts and still be at factory oil specs.

I'm not thinking right now if the same holds true for the trans, but I don't see why it wouldn't.
 

doublespaces

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I am trying not to think hard, but I added 2.5 quarts of engine oil capacity to an engine I built a while back. Engine had known documented problems with running the pan dry like dyezak mentioned. Another major advantage on this setup was a significant safety margin if I ran low on oil. Basically I could lose 2.5 quarts and still be at factory oil specs.

I'm not thinking right now if the same holds true for the trans, but I don't see why it wouldn't.

Doesn't that depend entirely on where the oil pick up is at and how the pan is designed? I don't even know how it works or what it looks like but I'd think that simply making a deeper pan wouldn't help you there.
 

Aaron

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That's how I upgraded capacity on the motor was a deeper pan, but I also lowered the pickup by the same amount. So the pan basically added 1.5" depth, and I lowered the pickup 1.5" as well.
 
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Blue335is

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More options the better. You could as Kris @ SSP. Im sure those selling the pan can at least give you the "sales pit" on the product.
 

juld0zer

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A Russian bloke on the other forum claims less/no hesitation from a stop with an extra litre of fluid. But his car has slicks and his issue usually follows heavy braking.

His theory is based on the M3 GTS fluid refill procedure. Same transmission casing and sump pan. M3 (all variants) have the external oil to air cooler, but the GTS calls for an extra litre after the normal oil balancing procedure is done.

Is oil surge really a problem?