Trans cooler: How big is too big?

[StuC]

Hey all, this is for my tow vehicle/daily falcon but i guess is generic enough to carry across to all automatics.
How big is too big for an external oil cooler? I will be bypassing the radiator cooler as they are prone to cracking and just be running this up front on its own.
I will be towing once a month and cruising on freeways for 100kms a day Mon-Fri not really giving it a workout at all. No skids, racing or burnouts in this thing.


Large: 960mL capacity plus lines. Does it seem reasonable enough?
http://www.ebay.com.au/itm/Oil-Coole...item3387841918

Extra large: Too big with approx 1.35 litre capacity plus lines?
http://www.ebay.com.au/itm/Oil-Coole...item4ae0d94bbf

Or something wider and thicker and approx 1.2 litre capacity plus lines?
http://www.ebay.com.au/itm/AEROFLOW-...item258403941e


Cheers guys and gals

Stu

[1JZ-Rolla]

Talking to gearbox builders when I still ran auto for drags/circuit/street, the consensus seemed to be that the trans fluid couldn't really be too cold. By that logic they all suggested fit as efficient a cooler as you can. Clearance of components/valve systems in the box don't appear to be as critical as an internal combustion engine, i.e; it's not the same as running your engine cold all of the time, increasing wear etc.

I think that regardless of whether you run a cooler or not, when running on the freeway with the converter locked, the trans fluid temp will drop well below normal operating in any case (excepting systems that flow through the radiator end tank - effectively heating the trans fluid to some extent when cruising.)

Cheers
Phil

[StuC]

Thanks Phil, good enough for me. I was under the same impression that it was going to get bloody hot regardless and couldn't really be cooled below 'normal' operating temps with the standard off the shelf items. If i chucked a full radiator sized cooler in it...then yeah, way too much but all of these would/should be fine.

Wrecker hunting this arvo....