Transmission cooler lines

[joedown]

I need to put in a SD tranny cooler. I was wondering if anyone has upgraded the cooler lines to the bigger ones like the super dootys use? Anyone make them or can you use the ones from the SDs?

 

[Biggreen96]

Yes you can upgrade to the bigger lines . Its a common upgrade wanting to do this myself but funds are tight right now . Get ahold of OBSWIZ and he can get you part numbers for the lines and everything.

 

[OBSWIZ]

SD trans lines

Line F81Z-7A031CE

Line F81Z-7A030CA

By Pass Tube 2C3Z-7H322-BA

I'd just use a LPD47391 Tru-Cool 40,000 GVW rating

 

[joedown]

Tell me about this. What's the bypass tube for? And what is the LPD47391 Tru-Cool? A filter?

SD trans lines

Line F81Z-7A031CE

Line F81Z-7A030CA

By Pass Tube 2C3Z-7H322-BA

I'd just use a LPD47391 Tru-Cool 40,000 GVW rating

 

[trackspeeder]

The bypass is to prevent damage if the cooler becomes plugged.

LPD 47391 is a tranny cooler.

 

[Marty]

If you want I have a line kit you can purchase. I use pushlock so if you want an external filter its simple to install.

 

[Tom S]

Which SD cooler are you planning on using? I have the one Cary mentioned mounted to teh back of the bumper.

 

[joedown]

Which SD cooler are you planning on using? I have the one Cary mentioned mounted to teh back of the bumper.

I had forgotten about the bumper mounted one. Since I have an intercooler it will probably be easiest to go with that one. Any big differences? How easy is it to mount?

 

[PsRumors]

SD trans lines

Line F81Z-7A031CE

Line F81Z-7A030CA

By Pass Tube 2C3Z-7H322-BA

I'd just use a LPD47391 Tru-Cool 40,000 GVW rating

What about the fittings in the radiator? Do they need to be changed or does it get bypassed?

 

[Mark Kovalsky]

Don't bypass the cooler in the radiator. You will lose A LOT of cooling capacity if you bypass it.

 

[Strokersace]

I've upgraded to the SD lines and factory 4r100 bypass tube. Run a 6.0 trans cooler. I preferred using the factory bypass setup instead of the Tru-cool setup because if there is any restriction in front if the trans, it'll bypass fluid to the return side right at the trans. It'll bypass everything in front of trans - lines, radiator, cooler. The Tru-cool w/ bypass only bypassed the cooler from my understanding and still leaves the trans vulnerable if there's a restriction anywhere in between.

As for the fittings in the bottom of the radiator, I swapped them out for larger ones, 1/2" on mine since I'm running a 6.0 cooler and 3/8" on my dads since I installed cooler equivalent in rating to the Tru-cool that Cary posted. Both systems work really good.

 

[Mark Kovalsky]

The factory bypass and the Tru-cool bypass have different functions. The factory bypass is there to bypass the coolers if there is a restriction. This preserves the flow to the lube circuit. The logic of this is that a trans can live for a while with no cooling, but it can only live for a few seconds with no lube flow.

The Tru-cool can only bypass the coolers when it is cold. Once it reaches it's set temperature it opens, sending fluid to the cooler. If there is a restriction this bypass can't do anything about bypassing the coolers.

 

[Charles]

The factory bypass and the Tru-cool bypass have different functions. The factory bypass is there to bypass the coolers if there is a restriction. This preserves the flow to the lube circuit. The logic of this is that a trans can live for a while with no cooling, but it can only live for a few seconds with no lube flow.

The Tru-cool can only bypass the coolers when it is cold. Once it reaches it's set temperature it opens, sending fluid to the cooler. If there is a restriction this bypass can't do anything about bypassing the coolers.

I had always assumed the line between inlet and outlet fittings on my 4R was a also a thermostatically controlled bypass as well, in that it would restrict or shut off flow through the coolers until the fluid reached a given temperature.

But no? The trans just makes do with no thermostat in the winter?

 

[Mark Kovalsky]

The trans just makes do without a thermostat in the winter. There is no thermostat in the 4R100.

 

[Charles]

The trans just makes do without a thermostat in the winter. There is no thermostat in the 4R100.

So the converter is left unlocked to make up the difference, or the fluid is run through the bottom of the radiator, making use of the thermostat in the engine.

Since I don't have my trans plumbed into my radiator, I will continue to leave the converter locked until the trans fluid reaches 40 or 50 degrees or whatever I have it set to. Usually takes a few miles to lock up.

 

[Mark Kovalsky]

The converter is left unlocked when the trans is cold because the control system is unstable and the unlocked converter helps warm the engine and trans faster.

The radiator NEVER warms the engine. NEVER. I have tested this from -40°F to +115°F ambient temperatures. I measured the ATF temperature in and out of the radiator and the coolant temperature inside the radiator near the trans cooler. The engine coolant was ALWAYS colder than the ATF. ALWAYS. Not sometimes, ALWAYS.

The cooler is in the tank where the coolant has already passed through the radiator and been cooled. The engine thermostat doesn't have much effect on this temperature. When it is cold outside the coolant around the transmission cooler is very close to ambient temperature.

It's a transmission COOLER, not a warmer.

 

[Charles]

The converter is left unlocked when the trans is cold because the control system is unstable and the unlocked converter helps warm the engine and trans faster.

In my case it's unlocked because I say so, lol. I programmed the temperature I wanted the converter to stay unlocked until so that it could heat my fluid up quickly and I wouldn't be driving around with molasses in my trans. It usually only takes a mile or so for it to lockup being as I live in the foothills of the Appalachians.

In my case it doesn't warm my engine as they are disconnected, but I take it that it would if they were.

The radiator NEVER warms the engine. NEVER. I have tested this from -40°F to +115°F ambient temperatures. I measured the ATF temperature in and out of the radiator and the coolant temperature inside the radiator near the trans cooler. The engine coolant was ALWAYS colder than the ATF. ALWAYS. Not sometimes, ALWAYS.

It surely warms the fluid in my ZF6 on my 550, which is why I left the fluid running through the radiator before hitting the cooler in front for winter time. Surely driving around empty at low speeds the radiator is at a higher temp than the trans. Maybe not, it is a large unit with lots of airflow. I would have never guessed. Poor trans...

The cooler is in the tank where the coolant has already passed through the radiator and been cooled. The engine thermostat doesn't have much effect on this temperature. When it is cold outside the coolant around the transmission cooler is very close to ambient temperature.

It's a transmission COOLER, not a warmer.

Well, most coolers are designed to keep the fluid at a design range.... not simply hold it below X and anything down to frozen solid be damned.

Apparently the trans is inefficient enough with the converter unlocked to maintain high levels of heat even with full ambient cooling. This also means that the cooler must be sized small enough so as to not keep the trans fluid horrifically cold in winter at light load, making it marginal in summer at heavy load.

It would be like an engine cooling system that employed no thermostat as well. It could be done so that winter weather operation was only moderately hard on the fluid, and summer weather operation only marginally scorched it.

A thermostat would seem a better choice, but apparently things work acceptably without one.

 

[alradco]

Don't bypass the cooler in the radiator. You will lose A LOT of cooling capacity if you bypass it.

Why is that?

 

[Charles]

Why is that?

Because it's a liquid to liquid cooler with a heat transfer roughly 14 times greater than a liquid to air unit, and he already stated that the fluid in the bottom of the core surrounding the trans cooler section is roughly at ambient temperature, meaning you're getting that huge jump in cooling capacity through liquid to liquid and the cooling media is roughly the same temperature as what's running through the liquid to air unit in front.

 

[Mark Kovalsky]

In my case it doesn't warm my engine as they are disconnected, but I take it that it would if they were.

It helps warm the engine because the engine is running a higher RPM with the torque converter unlocked.

It surely warms the fluid in my ZF6 on my 550, which is why I left the fluid running through the radiator before hitting the cooler in front for winter time. Surely driving around empty at low speeds the radiator is at a higher temp than the trans. Maybe not, it is a large unit with lots of airflow. I would have never guessed. Poor trans...

So we have a choice between what you hope is happening and what I have measured is actually happening. Hmmmm...........the radiator cold tank is at ambient. How is that warming your ZF6? The transmission is colder than ambient temperature?

Well, most coolers are designed to keep the fluid at a design range.... not simply hold it below X and anything down to frozen solid be damned.

Apparently the trans is inefficient enough with the converter unlocked to maintain high levels of heat even with full ambient cooling. This also means that the cooler must be sized small enough so as to not keep the trans fluid horrifically cold in winter at light load, making it marginal in summer at heavy load.

Yes, that would have been a good way to do it, but it wasn't to be. The coolers were ONLY designed to keep the trans below it's maximum temperature at worst case cooling. No thought was given to cold weather operation until much later. That's why the TorqShift and all newer transmissions have thermostats.

A thermostat would seem a better choice, but apparently things work acceptably without one.

The transmission operation is very marginal at extreme cold temperatures. The system was optimized for extreme high ambients at maximum loads.