Besides the fittings, that is.
Both seem to be made to circulate viscous liquid, and Auto Trans Fluid is pretty much a set weight oil with different additives. Are transmission coolers in any other way different from an oil cooler?
Besides the fittings, that is.
Both seem to be made to circulate viscous liquid, and Auto Trans Fluid is pretty much a set weight oil with different additives. Are transmission coolers in any other way different from an oil cooler?
It depends on sizing. You can use an engine oil cooler as a trans cooler, but not all trans coolers can flow enough or handle big enough in/out ports to be used as an engine oil cooler.
Flow, that's it.
I used an engine oil cooler as a power steering cooler on an older car and it seemed to work fine. I used ATF in my power steering.
Check the pressure ratings. I believe transmission cooler setups often run at a lower pressure than oil systems do, so it's possible that a heat exchanger originally sold for transmission cooling duties might not stand up to use as an oil cooler.
That's exactly what I needed folks, thank you. I'm going to try to use an oil cooler as a transmission cooler, so it seems that I'm in the clear.
They're TOTALLY DIFFERENT. One cools the engine oil and one cools the transmission oil. Duh.
Dr. Hess beat me to it ... that was going to be my smart a$$ answer 
I'd have been disappointed if I didn't get some sarcasm in reply.
Engine coolers need to handle up to at least 100psi(most pumps bypass about 85-90+) as they are usually plumbed in right before or after the oil filter which sees full pump pressure.
Trans coolers typically are the last/near last hydraulic part in the system as they're under very little pressure. IIRC in many cases under 30psi max.
Slightly related:
What are some decent oil and/or trans coolers that are plentiful in a typical junkyard? You know, for science.
In reply to maschinenbau:
rx7s have massive oil coolers, ive seen some fair sized "aux" trans coolers big enough on things from 4cy turbo auto Volvos to trucks with towing packages ( great place to look) also theres been a handful of cars with water to oil coolers that could be adapted easily I believe, one that comes to mind is 1.8 miata
1st gen MR2 had a oil to water oil cooler.
Never EVER use a used oil cooler x2 if its a junk yard unit, You might as well use a drained used oil filter. Coolers are notorious to get clean they heat up and crap comes out of places that never got cleaned. Good coolers are out there for a lot less then a rebuilt motor.
B&M (as well as others) both sell nice units with stacked plates and two side tanks that offer little to no flow restriction but cool great. I used many of the 8x11 unit on my race cars that were oil cooled motor cycle engines running 200psi in the oil cooler never an issue unless contact was made. Ran the same cooler in my 38ft bus for the Allison auto trans as it was originally a manual trans radiator. I always used the 1/2 piped inlet units never a barbed fitting and real hydraulic hoses. back then they were $70 from the big box speedshops.
No coolers with 180 deg bends, bends equal less efficiency.
Brett_Murphy wrote: I'd have been disappointed if I didn't get some sarcasm in reply.
I'll apologize for both me and the good Doc ... we were just slow to get things together this time ... we promise to "try" to do better in the future 
44dwarf you have a VERY good point, it's really important with used auto coolers as well. But! Autozone and the likes sells a can of foaming E36 M3 to clean out all the gunk, I did it myself when I bought a used trans cooler and knock on wood had been okay but yes never forget the possibly amount of crud in a used cooler. Obviously if it was a brand new motor if suggest a new cooler...but in the grassroots spirit...foaming trans cooler cleaner works
If you're relocating the filter along with the cooler install and worried about a used cooler, put the filter downstream of the cooler / t-stat. That should keep any crud that comes out of the cooler from ending up in the motor.
My plan is to route the transmission lines out of the radiator and use the transmission/oil cooler as the sole means of cooling. I may have to run two in series.
Can't tell if you mean delete the rad "cooler" but it's just as dangerous for a trans that's too cool than too hot, that's why from the factory even hd trucks the oil is pre cooled or preheated by the rad and then goes to the air to air trans cooler then back. I'll admit I'm running just an air to air cooler on one of my cars but I also have a spare trans sitting right beside it so I wasn't worried. Just something to think about.
The in-rad coolers do nothing to prevent over-cooling. On the highway with the TC locked in the winter is when the trans is at most risk for over-cooling, and the cold side of the rad (where the heat exchanger is) stays pretty cold in that situation. And it's basically an infinite heatsink until the engine warms up and the t-stat opens anyway.
Plus, most transmissions can tolerate pretty cold fluid without issue, although some will alter their shift strategy or start to feel weird when they're too cold. I've run air to air with no t-stat for 90k miles with no issues (adding one soon though, as it does over-cool in the winter and probably costs some driveline efficiency with the thicker fluid).
I worry more about the radiator failing and taking out the transmission with it due to contamination of the fluid.
You'll need to log in to post.
