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Custom tranny cooler lines/remote filter??

dangerousdave said:
Leroy, what's a price for this? How much are the replacement filters, too?
http://perma-cool.com/Catalog/Cat_page25.html

I got a filter from Rockauto that looks good on their site, but its too small in person. I'll stick it on my son's Mitsu.
I'll need one of these for the Burb.
So glad you weighed in on this.
Click to expand...

Hey sorry for the delay, been running crazy here lately. I will have to get back on the prices later.
I have heard of the radiator cooler as actualy being a preheater for the trans fluid. Would be nice if you could bypass it once the fluid is warm.
 
That's the problem.When the tranny is getting too hot it is also going to overheat the engine by sending very hot coolant into the engine. A seperate system would have to be better. No other piece of equipment i've worked on dumps a hydraulic system heat directly into the engine as these do.
 
I bet with one of the oil tstats from Perma Cool you could bypass the radiator after fluid is warm. In the tstat normal operation it is going to bypass the cooler and return oil to the trans (or engine) until warmed up. What if you plumbed the tstat inlet like normal, but the "cold return" port is plumbed to radiators cooler. Then when oil warms up the tstat switches the flow to the other outlet port (The one that in a normal "hook up" would have gone to the radiator) and off to the aux cooler.
Im pretty sure it could be done, but I would have to draw it all out on paper to get my mind around it. Maybe someone with more know how than me can post a drawing up of the circuit.
 
IIRC sometime within the last year this was discussed. There was a thermostatic bypass that would bypass the rad cooler when the oil got up to temp.
 
Here is the instruction sheet. Looks like a bypass operation could be done to me. What do the other doctors think?

scan0001.jpg
 
In my experience with 5 trans coolers added on as many vehicles, the radiator "cooler" is junk, unless you live in ice, in which case you need heaters not a cooler.

The trans can warm itself up just fine, thank you, as does the motor. If you MUST use it, put it before the aux cooler, IMO. The one freightliner with autoshift I drove had no in-rad "cooler", IIRC.
 
The trans oil will get up to temp before the coolant does. No real need. Trans cooler is on the cold side of the radiator so that really doesn't work.
I do think the thermostat plumbed to bypass the cooler and filter is a good idea.
Another thing is to convert to 3/8 at the transmission. The factory 5/16 inverted flare lines are difficult to convert to 37 degree AN or NPT.
 
Hope its ok to chime in here.

There are a few reasons why the manuf. has the cooler in the rad ,

One is to heat the oil , in colder temps the oil will gel if it does not go to the rad

when in slower city traf there is little to no air flow to cool the external cooler .

As was said in early post the trans temp climbs in slower speeds then as your speed climbs the temp falls . The air flow is increased and also the torque convertor locks up. In the 4l80 it locks above 45-46 mph. keep in mind that over 95% of all the heat in a auto trans in produced in the convertor when it is not locked up. you will also see on the hwy that the temps as a rule will stay lower then when driving in the city. This again do to the lockup being applied and more air flow.

If you by pass the rad cooler you should put a pusher fan on to the external cooler for the slower (less air flow ) conditions. also make sure to have a larger than normal external cooler if you by pass the rad.

over the years I have bypassed a few rad coolers the owners have said that they did not notice any drop in engine temps.

If you are not in a cold climate then you can not get away from the rad cooler. Here in Canada there is no way you can in the winter months.

All of the cooled oil that goes back to the trans is used as lube oil for the gear train you gel that oil or stop the flow it an't pretty .

most oil coolers now have a bypass built into the inlet side of the cooler so if it does gel / block it can bypass
 
SnowDrift said:
Radiator cooler first, then to the external. My wife's gasser Burban and my truck are both the same way from the factory. I added one to my '90 gasser years back and that's how I plumbed it, as well.
Click to expand...
If, in fact this is how the cooler is plumbed from the factory, then in extreme cold the trans fluid would gel or get too thick to flow. There is no type of thermo bypass from the factory ,that I know of. :confused:
 
been more the one tranny burned up here in AK. Also have to watch out for the aftermarket coolers. The good ones like the oem ones have a passage in them that will still let some fluid thru it if it's real cold. Some of the aftermarket ones don't and will basically plug up with thick oil and burn the tranny up.
 
By using this http://perma-cool.com/Catalog/Cat_page14.html You would still get a small amount of flow through the cooler to keep the cooler sumwhat warm. The majority of the tranny fluid will go back to the tranny untill it gets warm enough. I don't see the need for the cooler in the radiator.
 
ak diesel driver said:
been more the one tranny burned up here in AK. Also have to watch out for the aftermarket coolers. The good ones like the oem ones have a passage in them that will still let some fluid thru it if it's real cold. Some of the aftermarket ones don't and will basically plug up with thick oil and burn the tranny up.
Click to expand...

This is why I went with the Derale with the temp switch controlled electric fan the heat exchanger is always open to flow, if I was running off road more than what I do, I'd put longer hose on it and move it to a higher spot than where it currently is under the bed.

My system capacity with pan, extra cooler & plumbing is 24 qts I think without draining the torque converter, this extra capacity aids in keeping things cool as well as there is more fluid to carry the heat.

When I started building for power I took a step back and looked at the total drive train system looking for sources of heat and ways to shed it. the extra cooler @ 25K rating may be too big as I hardly ever need to turn on the power switch for the fan, my trans pan temps are always 200F or less.

This must be working as I seem to have some of the lowest coolant temps, which I think are held in check when pulling hard by maintaining the in radiator water/trans interface, the tranny cooling aiding to help shed engine heat, vs the engine coolant keeping the tranny cool as this circuit is normally understood to be doing.

My oil bypass dual filts bringing the oil system to nearly 2 1/8 gallons also means more heat xfer happening there as well with some minor passive heat rejection as more air flows over the oil filts better that it does tucked up tight up by the engine.

One day with time off & $$$ to buy the sensors it would be interesting to do a heat load/rejection study on my 6.5 with all the cooling improvements, as we are operating way beyond what the General ever thought the 6.5 could do in creating heat at higher power levels.
 
Last edited:
dangerousdave said:
Leroy, what's a price for this? How much are the replacement filters, too?
http://perma-cool.com/Catalog/Cat_page25.html

I got a filter from Rockauto that looks good on their site, but its too small in person. I'll stick it on my son's Mitsu.
I'll need one of these for the Burb.
So glad you weighed in on this.
Click to expand...

OK, the kit with gauge #10677 is $90
W/out gauge #10678 is $50
Replacement filter $15
plus shipping.
 
Free your mind of the compromise made to keep using the radiator intercooler.

Bypassing the radiator removes the risk of coolant getting into the transmission. I have paid for several transmission rebuilds from the radiator intercooler tank getting a pinhole leak. The leak is so small that fluid changes just about cover it up. Aside from doing oil samples on the transmission that I have not done in the past the only sign of this pinhole leak is rust appearing on the top of the trans dipstick. Water dissolves the glue used in clutches and coolant mix rusts bearings. Till they lock up and spin costing extra to get the bearing support in the case welded up and re-machined on rebuild.

Putting the air to oil external trans cooler in front of the condenser adds heat to the stack, but, gives the cooler constant airflow because the clutch fan is always moving air at its 20% lockup minimum. Put the biggest cooler you can fit in front of the radiator and you should be fine. Out here I did this and had no issues towing with my Yukon on the rebuilt trans from pinhole leak radiator - and I did not have to replace the radiator.

The radiator acts as a surge absorber from the transmission for it's only benefit. This heat surge has to go through the engine before it reaches the cooling section of the radiator. Getting really hot will put bubbles to the intake of the water pump and cause cavitation. Say your OD has failed and you are running direct,3rd, to the trans shop for a rebuild and the trans temp gets over 240 like it did for me. Radiator only intercooler alone is simply known to not do the job when you put a heavy trailer on and put the hammer down. (esp. like you have to on a 6.5 towing.)

When cold the radiator intercooler does not warm up the transmission. Depending on what you are doing the transmission can warm up the engine from a cold start. If the radiator did warm up the fluid why does the fluid then go to the air to oil intercooler? Simple, to get the coldest oil possible back to the transmission. This is a cooling circuit not a heating circuit.

In the end you want to get the heat out of the transmission to the air. Using the middle man of the engine's coolant gives you losses in efficiency.

As far as electric fans on the cooler I suggest the KISS method. Power the fan with the ignition. Let the cold fluid bypass do it's job and avoid the expensive temp switch. The switch is one more failure point and 2 connections. Plus you can test the fan at key on and know it is working: not jammed with a rock or failed.

As far as 6.5 experience towing flat out on the 7% grades to Payson,AZ and beyond I am not happy with the use of both coolers: an air to oil and the radiator intercooler with radiator first in the hot oil flow. This is where you find out that engine temperature and transmission temperature are independent. Engine can be reaching 210 and the trans can be at 180. Forced to 3rd without the TCC locking up the trans can hit 220 and the engine below 210 with the fan screaming. I learned to let off the throttle and back into it to 'trick' the computer into locking the TCC. This would allow me to pick up a couple MPH vs. a unlocked TCC. A TCC lockup switch helps trans heating more than coolers can.

My trans shop says the 4L80E runs hot. So the above is acceptable, but, not the best.

Another vehicle I have with a larger, thicker, radiator installed still burned up the transmission with only the radiator intercooler in use. So risk coolant in the trans and it still doesn't do the job...

Climbing the grapevine with a sedan - pried the trans filter out in chunks from heat making it brittle. Added a truck size trans cooler and never had an overheat problem again.

I would use a trans temp gauge to evaluate your results.

bk95td said:
If, in fact this is how the cooler is plumbed from the factory, then in extreme cold the trans fluid would gel or get too thick to flow. There is no type of thermo bypass from the factory ,that I know of. :confused:
Click to expand...

Factory air to oil coolers have the bypass controlled by viscosity.

Quoting B&M's site:

feature known as “Low Pressure Drop”. The coolers assembled with hose barb ends include a unique bypass feature allowing a controlled amount of ATF to bypass the stacked plate core when the fluid is cold. This is beneficial in cold climate areas to guard against lube system failure. Controlled by viscosity, fluid is returned directly to the lube circuit through bypass openings in the stacked plate core. As the temperature increases, more ATF is directed through the core. This highly efficient design combines improved protection against lube system failure with the required levels of optimal heat transfer.

http://www.bmracing.com/PRODUCTS/Au...on-SuperCooler-rated-at-14-400-BTU-11x6x1-1-2
 
I read you and get your point WW but to have happen what you describe requires a lot of things going wrong, if the problem was that big of a concern every vehicle with a auto trans is at risk to what you postulate as being a concern, as radiator cooling of trans fluid is the primary and only method to cool a trans for most and were coolant leak an issue I think we would have more posts with this.

Your scenario also precludes that by design some protection for water in trans from rad is going to be difficult as trans operates at a higher pressure than cooling pressure, unless you are having combustion gasses leak by an pressurize the cooling system, Cooling systems run maybe 18 psi, trans is much higher (I don't know pressure at the return to the trans) but it is significantly higher.

Now I suppose on shutdown the residual pressure in the cooling system could admit coolant to the trans side of the system through a pinhole in the trans cooler side of the radiator.

I would expect that trans levels would go up and radiator levels would go down if this was occurring with volume that would create problems to the trans clutch pack, water is present in trans fluid constantly via condensation from temp swings you cite as the trans is vented to atmosphere it can pull in high humidity air over time, as you say minimal water entrained in trans fluid goes away when fluid/filters are changed.

As for the key on trans cooler fan that would work but since the electric fan is my secondary means of cooling I have opted to make it a selectable powered option, controlled by the temp switch, and it is easy to know if the fan is or is not working via monitoring the trans temp, or listening for it, that fan is very loud when it is on.

Lets say both strategies work, just a matter of what works for you; I prefer not to restrict air flow to the engine by adding a large ATA trans cooler in front of the condenser/rad despite what I consider a remote possibility of cross contamination coolant to trans. Plus IMO there would be a loss of mpg/hp with constant engagement of fan clutch, which engagement is controlled by the temp of the air coming thru the heat exchanger stack.

WW this reply was not to nullify your experience or theory just to offer an alternative opinion so please take it as that, as with most things multiple ways to skin a cat, none necessarily correct or incorrect, so long at the end of the project the cat gets skinned, and you didn't cut yourself during the skinning :thumbsup:
 
Since my stay at the Holiday Inn Express did not make me a transmission expert, my forte being turbines, I'll move this to the transmission section where real transmission experts do hang out, and see what those folks have to offer up on this discussion.
 
I've lost 2 transmissions due to leaks in the cooler inside the radiator. The tranny shop told me it takes less than a teaspoon of anti-freeze to disolve the clutches ,so there was no noticeable difference in coolant or trans fluid levels. By the time I saw tranny fluid in the radiator it was too late.
 
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