Ditching the factory ATF cooler and going only aftermarket

[Guest]

Anyone here running their automatic transmission with ONLY an aftermarket cooler? That is, taking the factory radiator-based cooler totally out of the system. I'm sure there must be at least a few people who have fitted aluminium radiators and are doing this out of necessity.

I'm asking because I want to know if it helps the transmission fluid to warm up to operating temperature quicker. My thinking is that a lot of the heat in the ATF is drawn out into the cold radiator coolant, which isn't circulated until the engine is properly warmed up and the thermostat opens. This is effectively chilling the ATF and prolonging the warm up cycle. Faster warming ATF should mean that we see smoother shifts a lot sooner after ignition start.

Of course I do always warm up the car, but only for a few minutes until the revs drop. I'd be sitting around forever if I always waited for the temperature needle to go fully up to normal operating temperature.

 

[smitty]

As I understand it, don't the aftermarket transmission coolers do a little too good a job? Isn't that why we route the lines through the aftermarket one first to cool the fluid, then back through the standard cooler to bring it back to optimum operating temperature?

 

[Guest]

Yes, but that doesn't really relate the the warming up procedure. In the morning especially, the radiator will be acting like a stone cold heatsink for quite a while before the thermostat does its thing.

 

[smitty]

So bypassing the radiator would (hopefully) lead to the trans oil heating faster in the mornings, but even when the car's warmed up the external trans cooler would still be overcooling the oil, without the factory one to bring it back up to optimal temp.

Personally I'd rather let it warm up that little bit longer, and know that the trans oil is at the ideal temp at all times... but thats my two uneducated cents.

EDIT: Just ignore me, some discussion about this here.

 

[snickells]

Hmmm.... what about a small thermo fan on a separate radiator specifically for the auto fluid with a thermo switch for activation?

 

[bradc]

The water heats up very quickly and helps get the gearbox up to temp. Even at the bottom of the rad it gets above 30C very quickly. Someone in the UK did try it a long time ago and it did take a lot longer for the trans to start acting properly.

 

[Guest]

I note the thermostat begins to open at 82c and is fully open at 95c, so the question is now how long does it take the engine block to heat the coolant > 82c before the thermostat will open? Until then the coolant will not be assisting heating of the ATF. Of course, there will be a difference between a car that has had a chance to fully cool overnight and one that has been driven only shortly beforehand. I guess there is only one way to tell for sure... acquire some data.

With all the alloy radiators people have been fitting lately, there has to be a number of people running their cars like this now without the factory coolers.

And yes, a cooler with a thermo fan like the B&M ones are what I'm thinking about.

 

[snickells]

Awesome. I look forward to reading about your adventures!

 

[king_panther]

Hey I've got a trans cooler in the Super. I start her up & put it in N & it doesn't take long at all to warm up.

Though point me out if I shouldn't be doing that.

 

[Guest]

KP, do you still have the factory cooler in the radiator in use?

 

[pauly]

Anyone here running their automatic transmission with ONLY an aftermarket cooler? That is, taking the factory radiator-based cooler totally out of the system. I'm sure there must be at least a few people who have fitted aluminum radiators and are doing this out of necessity.

I'm asking because I want to know if it helps the transmission fluid to warm up to operating temperature quicker. My thinking is that a lot of the heat in the ATF is drawn out into the cold radiator coolant, which isn't circulated until the engine is properly warmed up and the thermostat opens. This is effectively chilling the ATF and prolonging the warm up cycle. Faster warming ATF should mean that we see smoother shifts a lot sooner after ignition start.

Of course I do always warm up the car, but only for a few minutes until the revs drop. I'd be sitting around forever if I always waited for the temperature needle to go fully up to normal operating temperature.

yeh im running after market ATF cooler, because yes, i got the famous RADIATOR crack..i got one of those fancy aluminum 40mm rads..and bought the ATF cooler from a company in altona...straight away i noticed how much smoother the ATM was, it was amazing, haven't regretted it....

 

[Hotwire]

Just realised, the Legnum is coming with a Koyo radiator so hoping the Japs did something regarding trans cooler... will hopefully know by the weekend..

And then will let you know how it goes

 

[gorgath]

Hey, I've got an aftermarket alloy rad and totally running my ATF directly to the aftermarker ATF cooler. In my personal opinion, it takes a about 6-7mins tops to get the ATF oil to get its temp before the tranny runs smooth. The way I do it is at cold start, I use the tippy and shift to 3rd gear and drive around 3k rpm.

 

[Guest]

Sadly that doesn't sound like the improvement I would have hoped for Irwin It seems similar to normal.

 

[pauly]

Sadly that doesn't sound like the improvement I would have hoped for Irwin It seems similar to normal.

Not dissing Irwin, but that is only his personal opinion , it isn't really concrete proof or evidence.. I'm sure many people who have after market ATF coolers opinion would differ....do wot u think and makes u happy.

 

[Guest]

Sure, people's experiences will differ and thanks for sharing yours Pauly... sounds like a positive result for you

 

[Dr_Josh001]

Been running just tranny cooler since getting the car 2 years & 40000km ago. No probs so far for me.

 

[Guest]

I did a bit of a bodgy test today, but interesting nonetheless. The car was stone cold after sitting for two days and it was 10 degrees outside. I measured the coolant temperature with a probe in the top of the radiator, and the transmission cooler core temperature with a probe jammed into the fins.

I idled the car for 5 minutes.

The transmission cooler steadily rose just over 1 degree/minute to a total of 6 degrees increase.

The radiator coolant stayed exactly the same for 3 minutes, after which it rose 1.5 degrees/minute for the final two minutes. Making a total increase of 3 degrees. Because this was so little I would put it down to the heat of the front exhaust warming the radiator core.

After this, I couldn't stand to see a VR4 sitting there idling and had to take it for a drive Plus I didn't want the thermostat to kick in and start spewing coolant out of the open radiator cap.

 

[bradc]

I would be interested to see the same test done with a probe in the water flow as well as in the atf piping

 

[Guest]

There's an ATF temperature sensor in the transmission near the sump, so I'm looking into tapping off a signal from that.