transmission cooler
- Thread starter gonzo
- Start date
9
934runner
Guest
I will do it.
bulldog-yota
New member
PROZAC said:
Yeah looks like I was wrong. I looked again at the oil cooler in front of the radiator, and the hoses also states A/T oil on it. It seems to indicate a flow from the bottom of the radiator connection through the cooler and then back to the tranny.
TechWrench
Senior Member
Koz said:
In all cases I have seen, any additional trans coolers are installed after the fluid leaves the radiator cooler. There are several reasons for this. Once the engine is up to temp, the temp of the radiator coolant remains pretty constant, but the trans temp can vary greatly, depending on the load. All heat in the trans is generated in the torque converter, and the harder it works the more heat it generates. This is why the trans cooling circuit usually takes fluid exiting the converter and sends it to the cooling circuit before returning it to the trans. As for the radiator cooler heating up the fluid when cold, I think this is marginal, at best. If you start off with both the engine and trans cold, the trans fluid will probably be up to operating temp before the engine because of the immediate 'work' the torque converter is doing. I don't know the specific amount of thermal exchange capable in the radiator cooler, but it would seem that it is a fixed amount. So, as I said, if the engine coolant temp remains fairly constant, then the temp of the fluid exiting the radiator cooler would depend on how hot it was when it entered. The harder you are working the trans, the hotter the fluid will get. And if the fluid temp can't be lowered enough by the radiator cooler alone, you need the extra cooling capacity of the add-on system. Over cooling the fluid is a much better situation than under cooling it. The trans is better able to handle lower fluid temps than too high. And once the fluid is damaged by overheating, it can't be fixed, only replaced.
TechWrench
Senior Member
Koz said:
If you want to trace the lines, the line closest to the front of the transmission is the pressure side to the radiator. The return line is the one closer to the rear of the transmission.
Just to add my .02....
The engineers understand properties and Laws of Thermodynamics better than the people in this forum.
The REASON you move HOT trans fluid to the radiator cooler FIRST is very easy and basic. Laws of Thermodynamics. Would you try and thaw a frozen steak with air or water? Water has the best Thermodynamic properties. And RUNNING water does an even better job.
Test: Take 4 frozen steaks. Which one of the following is thawed FIRST (shortest amount of time)?
1. Place steak no 1 in a 300 F oven.
2. Place steak no 2 in a pot of 212 F boiling water.
3. Place steak no 3 in a pot of 70 F water.
4. Place steak no 4 in a pot of 70 F running water.
Number 4 wins EVERY time! Why? Laws of Thermodynamics. Moving or running fluid, like the running fluid (coolant) in your radiator is a fluid to fluid exchange and is more efficient than an Air to fluid exchange. It will disapate heat more rapidly than the Air to fluid heat exchange.
(remember: hot trans temps go above 215 F and the radiator is a constant 190F)
You then take the cooled 190 F trans fluid now cooled from its higher temps to a secondary Air-to-Fluid exhange where it is further cooled before returning to the transmission.
Inter-coolers for Turbochargers are the exact same thing. Just a heat exchange. The inter-coolers that use water/coolant work better and can be smaller. The Subaru WRX-Sti uses a Air to Air heat exchange to give its engine a boost of denser air or cool the air heated by the turbocharger.
Best cooler in your engine? The oil circulating within!
The engineers understand properties and Laws of Thermodynamics better than the people in this forum.
The REASON you move HOT trans fluid to the radiator cooler FIRST is very easy and basic. Laws of Thermodynamics. Would you try and thaw a frozen steak with air or water? Water has the best Thermodynamic properties. And RUNNING water does an even better job.
Test: Take 4 frozen steaks. Which one of the following is thawed FIRST (shortest amount of time)?
1. Place steak no 1 in a 300 F oven.
2. Place steak no 2 in a pot of 212 F boiling water.
3. Place steak no 3 in a pot of 70 F water.
4. Place steak no 4 in a pot of 70 F running water.
Number 4 wins EVERY time! Why? Laws of Thermodynamics. Moving or running fluid, like the running fluid (coolant) in your radiator is a fluid to fluid exchange and is more efficient than an Air to fluid exchange. It will disapate heat more rapidly than the Air to fluid heat exchange.
(remember: hot trans temps go above 215 F and the radiator is a constant 190F)
You then take the cooled 190 F trans fluid now cooled from its higher temps to a secondary Air-to-Fluid exhange where it is further cooled before returning to the transmission.
Inter-coolers for Turbochargers are the exact same thing. Just a heat exchange. The inter-coolers that use water/coolant work better and can be smaller. The Subaru WRX-Sti uses a Air to Air heat exchange to give its engine a boost of denser air or cool the air heated by the turbocharger.
Best cooler in your engine? The oil circulating within!
Sorry for my being obtuse about this subject, but I have a 05 v6 towing a 4000 lb boat. Do I need a trans cooler? I can't believe Toyota would put on the tow package on the v6 w/o the trans. cooler if needed. And just for anyone's info, the gas milage I'm getting when towing is horrible. I maybe average 11 miled per gallon when towing the boat. I do tend to go a little fast though 70-75 mpg. I'm just anxious to get the boat in the water. Maybe going from chicago to kentucky lake this weekend. Little worried if I'm hurting the trans. Thanks for any information.
greasefingers
New member
IMO I would not tow a heavy load long distances without a tranny cooler. I thought every manufacturer supplied an additional external tranny heat exchanger, with a dealer supplied towing package. I guess I was wrong.
For a few years, I was towing my Dads 3500 lb boat twice a year with my Jeep. It had no tranny cooler, I installed the hitch, but it was only twice a year, a 6-mile trip, and all low speed driving on back roads. So I do not think that it constituted additional cooling. But highway driving is different; especially long distances. It would be a cheap Mod (probably under $ 100 for an aftermarket cooler) and if you plan on keeping the T4R for a long time then it would be a wise investment.
For a few years, I was towing my Dads 3500 lb boat twice a year with my Jeep. It had no tranny cooler, I installed the hitch, but it was only twice a year, a 6-mile trip, and all low speed driving on back roads. So I do not think that it constituted additional cooling. But highway driving is different; especially long distances. It would be a cheap Mod (probably under $ 100 for an aftermarket cooler) and if you plan on keeping the T4R for a long time then it would be a wise investment.
And, lastly, the reason that auto-trans vehicles have their fluid running through the main radiator is actually to pre-heat the tranny fluid. Trans cooling may occur under certain circumstances but to really cool you need the fluid to flow through its own heat exchanger (little rad up front or one you slap on).
Bob
Bob
Iowa4Runner
New member
05V8SPRT said:
I just have two quick questions...
1. Are you an Engineer?
2. Where did this steak question come from?
<Would you try and thaw a frozen steak with air or water? (and more)>
The Laws of Thermo deal with heat, not fluids. It's all about delta T (the difference in temp).
Water or air? You cool your beer with all the water you want; I'll cool it with air, -50'F at velocity. Bet I'll freeze it first!
The Laws of Thermo deal with heat, not fluids. It's all about delta T (the difference in temp).
Water or air? You cool your beer with all the water you want; I'll cool it with air, -50'F at velocity. Bet I'll freeze it first!
