Prefered Transmission coolers

Messages
702
Location
Midland, MI
Ok, so I am thinking about adding an external transmission cooler. The 2003 4Runner supposedly comes with a cooler that is internal to the radiator, I do not think I am keen on that idea when I know my radiator temps are hotter than I want my fluid to start with. Anyhow, any prefered manufacturers, and should I only consider coolers with built in bypass, in other words should I worry about my transmission fluid being too cold in the winter? I guess if that is a worry I could rehook it up before winter.
 
Messages
28
Location
Iowa
I was always taught that the transmission fluid line running through the radiator served 2 purposes. 1) To cool the fluid when it was too hot and 2) conversely, to heat up the fluid if it wasn't warm enough. With this in mind, best practice was to put the aftermarket cooler such that it comes BEFORE the radiator, so that any overage/underage in heat dissipation the aftermarket does will be mitigated by the factory designed cooler.
 
Messages
4,009
Location
Calgary Canada
B&M's best coolers are actually Long/Tru-cool LPD "stacked plate" coolers. They use cooler architecture so that changes in viscosity/temperate to function as a cooler bypass when cold. T They are very good coolers and are OEM from many manufacterers. My Avalanche had one, my Duramax has one and my neighbor's Toyota has one..all from the factory. I don't think you can do better.
 
Messages
3,773
Location
Houston, Tex
 Originally Posted By: Jim 5
B&M's best coolers are actually Long/Tru-cool LPD "stacked plate" coolers. They use cooler architecture so that changes in viscosity/temperate to function as a cooler bypass when cold. T They are very good coolers and are OEM from many manufacterers.
When you really start looking into it you will discover that most (if not all) stacked plate coolers are identical to these. It is reasonable to assume that the only difference is the brand on the box.
 
Messages
8,756
Location
RI
Junkyard is a great place to find ATF coolers. I'd look for any SUV/Truck from Toyota 1st. Then, adapt any of the other automakers. Ebay is good too if you don't want to go dumpster jumping. A piece of cardboard over the cooler solves all winter issues.
 
Messages
6,388
Location
Washington St.
I think there are two main makers of the coolers, Long Mfg. (Dana), and Hayden. I use the Long due to their internal bypass configuration. ATF (and every other fluid) needs to be normally warm. 140 to 160°F is good. Just how warm do you think the bottom of your radiator is? No one knows. It is cooler than the top of the radiator that is getting the hot coolant from the top of the engine as the radiator does its job...cooling things down. Anyone willing to take the temperature of the coolant leaving their radiator?
 

lobo11

Thread starter
Messages
702
Location
Midland, MI
speedbump, my thoughts as well the plan was to put the cooler on before the radiator. unDummy, good call on the cardboard, I like a practical solution, thanks. Looks like I have plenty of room in front of the radiator so I guess I'll go with a decent sized unit.
 
Messages
39,806
Location
Pottstown, PA
 Quote:
Anyone willing to take the temperature of the coolant leaving their radiator?
It depends, naturally, but you can figure if you're not overheating and staying around 210F+/- that the lower part of your rad isn't exceeding normal trans temp ranges. What you don't know is if the oil:coolant heat exchanger has enough capacity for what the trans is putting out. Usually similar conditions will send both upwards ..but not always. I have an auxiliary in line with the rad cooler. I'm debating on using a thermostat as a diverter valve. Below 180 to the rad ..above 180 to the auxiliary. ..but I like adaptive/reactive things.
 

lobo11

Thread starter
Messages
702
Location
Midland, MI
Ok, so on one of the Toyota truck forums most of the guys put their auxillary cooler right off the return line from the radiator to the transmission. So basically they tap the return line going to the transmission from the radiator cooler, run that to the auxillary cooler, then from the aux. cooler to the tranny. Obviously the most efficent way to get the fluid as cool as possible. If I need not worry about low temperature issues (i.e. poor shifting at extreme cold) this is the way to go. What say you guys, I think this is what I will shoot for and I will just block the air flow to the auxillary in the winter. Another thing I found strange. So Toyota's TRD parts division offers tranny coolers for the 4Runners until 2002 (Gen. 3) but they do not sell for 2003-2009 (Gen.4). Not sure if that means Toyota increased the size of the built in radiator cooler and they deem it sufficent or what???
 
Messages
1,209
Location
CA
That is how I have mine hooked up. Return to trans comes from the external cooler. I usually notice in the winter that OD takes longer to kick in until the fluid warms up, but it did that even without the external cooler. I have one of the stacked-plate coolers that functions as a bypass when the fluid is cold. Eventually I would like to get some sort of temp gauge for my trans, but for now I know it is getting cooler fluid at least!
 
Messages
3,772
Location
los angeles
 Originally Posted By: daves66nova
Is there a minimum temperature for the trans temp? I'm thinking that there isn't since it's hyd fluid, but i'm pretty sure i'm wrong,right?
bump
 
Messages
39,806
Location
Pottstown, PA
Some allege that the converters won't lock up until certain temp thresholds are met. In my case, it's not the trans temp that allows convert lock up, it's the engine temp.
 
Messages
2,097
Location
kansastan
I agree with GA on the ebay suggestion. The last tranny cooler I bought was from an '02 Ford Expedition. It had standard JIC o-ring inlet and outlets and convenient brackets. It fit nicely on the wife's '01 Lumina. Bigger than most aftermarket coolers, and cheap. I couldn't see any sign of fluid contamination, but since I didn't know the vehicle's history, I plumbed my inline filter in after the Expedition atf cooler. I plumbed the oil-to-air cooler so that the fluid flows through it first, then through the radiator. For what it's worth, that's how GM medium-duty trucks (Top Kick, etc.) are set up when running two tranny coolers: first through the oil-to-air cooler, then through the cooler in the radiator. Either way will work, but IMO, this method keeps the ATF temperature more stable AND avoids introducing excess heat directly into the engine's cooling system.
 
Messages
39,806
Location
Pottstown, PA
You don't get the moisture that you do with combustion in an engine. Someone did the math for me. You get 1.4 gallons of water for every gallon of gas you burn. I don't know how much makes it past the rings ..but the most you would have to deal with in an automatic would be the humidity that got sucked in via the vent when it cooled down. It should be easily purged in no time.
 
Messages
1,335
Location
Arizona
Seems some manufacturers differ with trans cooling. Most that I have run into route the cooler lines in this manner. Hot fluid from the transmission to the radiator, from the radiator to the auxillary cooler ( if so equipped) and back to the transmission. This seems like the most rational approach unless you were in a very cold climate and the cooler did not have a built in thermostat. If it were the other way around in my toyota, especially here in AZ where below freezing is a rarity, I would re route the lines asap! Just doesn't seem to make much sense to cool a fluid, only to rewarm it with the radiator.
 
Messages
39,806
Location
Pottstown, PA
 Quote:
Just doesn't seem to make much sense to cool a fluid, only to rewarm it with the radiator.
It's a debatable topic. I forget if it is a Toyota or not (I think it was) that uses a laminar cooler right on the trans that circulates engine coolant directly. No rad tank at all. They depend on the engine coolant to warm it and cool it. In the HD towing version, the fluid is only routed to the auxiliary cooler when the converter clutch is unlocked. Otherwise, it's 100% cooled by engine coolant. I've been rethinking my plan (prospective) to use a thermostat to divert flow from the rad tank to the auxiliary cooler. I can plumb it to flow normally to the rad ..then above 180F take a detour to the auxiliary before hitting the rad. I guess it could also be done on the outlet of the rad tank too. It would still involve just using 3 out of the 4 ports on the thermostat.
 
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