Transmission cooler question
#1
06-19-2012, 02:25 AM
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Transmission cooler question
Getting ready for camping season with my new to me '95 psd with e4od. I decided to add an additional trans cooler as the truck was 100% stock. My question is, I removed the radiator section (liquid to liquid) of the cooling system from the equation and added an additional liquid to air cooler. Will deleting the liquid to liquid cause me any problems or will this setup I have lower the temps better?
#2
06-19-2012, 02:51 AM
In theory, in the winter a cooling system with no liquid to liquid section could keep the transmission fluid too cold and it would not reach operating temperature.
In reality, unless you live in northern Alaska and/or drive a tiny econobox with an automatic that generates no heat for all practical purposes this does not happen. If this still concerns you, you may install a cooler with a thermostat (B&M sells these) which will keep the fluid from flowing through the cooler until it gets to operating temp. Another thing is that the liquid to liquid types can crack and you can get cross-fluid contamination without knowing about it until the fatal damage has already been done. Those cooler types' passages are smaller, too, so they clog easier.
Early Nissan Pathfinders have the same kind of in-radiator cooler we do. They cook their transmissions when that cooler plugs up with the normal debris in trans fluid and flow stops. The unofficial workaround is to bypass the stock cooler and fit an external unit. Pretty much every truck maker has run into problems with their radiator-mounted coolers where this is the solution, official or otherwise.
In reality, unless you live in northern Alaska and/or drive a tiny econobox with an automatic that generates no heat for all practical purposes this does not happen. If this still concerns you, you may install a cooler with a thermostat (B&M sells these) which will keep the fluid from flowing through the cooler until it gets to operating temp. Another thing is that the liquid to liquid types can crack and you can get cross-fluid contamination without knowing about it until the fatal damage has already been done. Those cooler types' passages are smaller, too, so they clog easier.
Early Nissan Pathfinders have the same kind of in-radiator cooler we do. They cook their transmissions when that cooler plugs up with the normal debris in trans fluid and flow stops. The unofficial workaround is to bypass the stock cooler and fit an external unit. Pretty much every truck maker has run into problems with their radiator-mounted coolers where this is the solution, official or otherwise.
#3
06-19-2012, 05:16 AM
That's a common theory, but it isn't backed up by data, or even by reality. It is just plain WRONG. Read the explanation above.
#4
06-19-2012, 05:39 AM
Deleting the liquid to liquid cooler will reduce your cooling by a large amount. That is a COOLER in the radiator, not a fluid heater. I have tested this from +115°F to -48°F ambient temperatures and I never found a condition where the radiator COOLER warmed the trans fluid. It does a great job cooling the trans fluid, so if you want your trans to cool put it back in the circuit.
If you think it does, explain this data if you please:
Transmission coolers - low temps and bypass thermostats - Tests and results - YotaTech Forums
There has been allot of talk about aftermarket transmission coolers and low temps. Well recently down here in Houston we have had temps in the low 20's the last two days so I thought it would be a good chance to take some temp measurements from the transmission cooler.
First off I have a B&M transmission cooler 70264 which is 14,000 BTU unit mounted in front of the condenser. I have the transmission lines routed to go from the transmission to the spin on filter which has my temp sender on it, then to the cooler and finally back to the transmission.
The cooler is designed with "bypass feature" as B&M calls it which allows the thicker colder ATF to bypass the cooler by going through two wider channels at the bottom of the cooler.
So now the results.
With the outside temps running in the low 20's I got in the 4runner that had been sitting all night and started driving. My house is just one street off the highway so there no stop and go, just back out of the driveway, go down the street and turn and get on the highway.
Well after 10-15 minutes of driving on the highway the transmission temp was hanging between 105-115 degrees and stayed that way for the rest of my 50 mile trip. On the way back I got into some stop and go traffic and finally with a good hard acceleration on the on-ramp I was able to heat the transmission up to 165F.
As soon as I got on the freeway I got in the left lane and put cruise on 75mph. As soon as I put on the cruise and saw from the tach that the torque converter had locked up, the transmission temp started to fall.
In about 1 minutes after the torque converter locked up the temp fell from the previous 165F down to 105-110F and stayed there from the rest of the 50 mile trip back home.
The above test proves that with the "self regulating" temperature design of B&M and most high quality transmission cooler that a in-line bypass thermostat is unnecessary. It also means that keeping the stock radiator/transmission cooler inline is unnecessary and very risky when you consider the ramifications if it fails and allows engine coolant into the transmission.
As far as the issue of how hot transmission fluid needs to be to function properly, I've spoke with several transmission techs and the going answer is 80-90F. My Chevy Duramax (hey I know but Toyota doesn't have a 1 ton diesel) which has just a large transmission cooler (no connection to radiator) runs around 100-115F also in the low 20's weather by factory design.
Another reason not to use a bypass thermostat or keeping the factory cooler piped in is heat. With just my B&M cooler during the 95-100F summer days this year my transmission never got above 125F on the highway with the torque converter locked up. During stock and go traffic or hard acceleration it would get up to 175F max but very quickly cool back down to the 120-125F range.
Any transmission technician will tell you the colder you can keep a transmission the long the transmission and fluid life will be. With the bypass thermostats your guaranteeing your transmission will never get below the thermostat temp which is normally 165-180F. With the stock transmission cooler still in-line your temps will vary with outdoor temp but in most cases will stay around 165-170F.
So if your considering a aftermarket cooler to protect your transmission from the risk of the stock radiator cooler failure or just want to keep your transmission cooler, forgo the bypass thermostat or keeping the stock cooler in line and just go with a good temp regulating cooler like the B&M or the IPT.
First off I have a B&M transmission cooler 70264 which is 14,000 BTU unit mounted in front of the condenser. I have the transmission lines routed to go from the transmission to the spin on filter which has my temp sender on it, then to the cooler and finally back to the transmission.
The cooler is designed with "bypass feature" as B&M calls it which allows the thicker colder ATF to bypass the cooler by going through two wider channels at the bottom of the cooler.
So now the results.
With the outside temps running in the low 20's I got in the 4runner that had been sitting all night and started driving. My house is just one street off the highway so there no stop and go, just back out of the driveway, go down the street and turn and get on the highway.
Well after 10-15 minutes of driving on the highway the transmission temp was hanging between 105-115 degrees and stayed that way for the rest of my 50 mile trip. On the way back I got into some stop and go traffic and finally with a good hard acceleration on the on-ramp I was able to heat the transmission up to 165F.
As soon as I got on the freeway I got in the left lane and put cruise on 75mph. As soon as I put on the cruise and saw from the tach that the torque converter had locked up, the transmission temp started to fall.
In about 1 minutes after the torque converter locked up the temp fell from the previous 165F down to 105-110F and stayed there from the rest of the 50 mile trip back home.
The above test proves that with the "self regulating" temperature design of B&M and most high quality transmission cooler that a in-line bypass thermostat is unnecessary. It also means that keeping the stock radiator/transmission cooler inline is unnecessary and very risky when you consider the ramifications if it fails and allows engine coolant into the transmission.
As far as the issue of how hot transmission fluid needs to be to function properly, I've spoke with several transmission techs and the going answer is 80-90F. My Chevy Duramax (hey I know but Toyota doesn't have a 1 ton diesel) which has just a large transmission cooler (no connection to radiator) runs around 100-115F also in the low 20's weather by factory design.
Another reason not to use a bypass thermostat or keeping the factory cooler piped in is heat. With just my B&M cooler during the 95-100F summer days this year my transmission never got above 125F on the highway with the torque converter locked up. During stock and go traffic or hard acceleration it would get up to 175F max but very quickly cool back down to the 120-125F range.
Any transmission technician will tell you the colder you can keep a transmission the long the transmission and fluid life will be. With the bypass thermostats your guaranteeing your transmission will never get below the thermostat temp which is normally 165-180F. With the stock transmission cooler still in-line your temps will vary with outdoor temp but in most cases will stay around 165-170F.
So if your considering a aftermarket cooler to protect your transmission from the risk of the stock radiator cooler failure or just want to keep your transmission cooler, forgo the bypass thermostat or keeping the stock cooler in line and just go with a good temp regulating cooler like the B&M or the IPT.
I've been getting some baseline temps with my stock in radiator cooler while I've been waiting for a warm enough day to install my aftermarket. Stock temps have been looking like an average between 124-168 with the air temps being between 14-35
Also, many non-American and non-Ford models don't have cooler-in-radiator setups, and 1) their transmissions seem to last longer, 2) if oil analysis is performed, their fluid seems to last longer before it starts breaking down, even given the same driving habits.
#5
06-19-2012, 01:34 PM
No, it doesn't. It does a horrible job of it, at least down South here.
If you think it does, explain this data if you please:
Transmission coolers - low temps and bypass thermostats - Tests and results - YotaTech Forums
If you think it does, explain this data if you please:
Transmission coolers - low temps and bypass thermostats - Tests and results - YotaTech Forums
I tested from -48°F up to +115°F ambients, and usually loaded to maximum GCWR.
What you quoted above is not a scientific test, it is a couple of people with little to no data speculating on what went on during a limited drive with no scientific process at all. There is NOTHING in that thread that proves anything one way or the other, other than it demonstrates that they don't know what they have or are looking at. And the first post even says he didn't have a radiator cooler. So how do you use that to show that a radiator cooler doesn't work?
The air to oil cooler wasn't getting enough airflow with the truck moving very slowly in reverse. By adding the radiator cooler the radiator became the heat sink for the ATF. That kept the trans cooler during low pseed situations. The air to oil cooler is ineffective at low speeds. The engine cooling fan does not draw enough air over the trans cooler, and the trans cooler can't add enough heat to the fan clutch to activate the clutch.
I'd like to see some data on that instead of unfounded claims on the 'net.
#7
06-19-2012, 10:01 PM
I have all the factory coolers plus a aftermarket cooler inline with them and my temps sit around 160*. With just the liquid and factory fin cooler they would sit 180* With just the two fined cooler (no liquid cooler) my temps would sit around 215*I did this to test how good each one cooled.
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#9
06-20-2012, 06:55 AM
Not only do we have the input from an actual Ford trans engineer, but stop and think about it.
The trans cooler releases heat into the engine's coolant which then releases that heat through the - huge - radiator. That's a lot larger than any air-to-oil cooler you can put in it's (internal trans rad cooler) place.
Yes, adding an additional air cooler will help drop temps, but you definitely always want to leave the oem cooler in the radiator.
The trans cooler releases heat into the engine's coolant which then releases that heat through the - huge - radiator. That's a lot larger than any air-to-oil cooler you can put in it's (internal trans rad cooler) place.
Yes, adding an additional air cooler will help drop temps, but you definitely always want to leave the oem cooler in the radiator.
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'17 6.7 F-250 KR ccsb 4x4
#10
06-20-2012, 08:41 PM
I have the in rad cooler and the trucool 4739 mounted in my bumper today it was 96 degrees outside my fluid went up to 145 degrees but when i stopped in traffic and sat there i got it up to 165 degrees and stayed there if i didn't have the rad cooler it would be about 200 degrees or more cause no air flow over the cooler so yes mark is right the rad cooler is cooling my transmission air not heating it up if you grab the lower hose of the radiator it is actually warm to the touch not as hot as the upper hose the radiator on the 7.3 is very efficient.
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