Transmission Cooler Essentials

[mstephens]

My Chrysler 300 Project TV

My trans temp without trailer at 70MPH is about 190F in 80F ambient conditions. I expect that to rise then to 210F in 100F weather, which is my neighborhood. That's before adding a trailer.

Feels too high to me. So, I am wanting to add a cooler. There are a vast array of products out there and none seem specific to my car. They appear to be kind of generic. I'd like to understand the different quality levels and to know how much cooling I can get.

From what I can tell, "plate and fin" is superior to other types. And, there is an issue regarding "pressure drop" which I can't quite quantify. The ratings on these are often expressed as some weight figure regarding towing, for instance: "towing 5000#" or "towing 2500#". I have seen also reference to "22,000GVW".

Hard to tell which brands might be quality and which might be junk. Since the majority of the cost involved is labor, it would be stupid to save $20 on materials if a higher quality unit is available.

Anyone have hands on experience with these coolers?

[Lance M]

Ask these guys.
Chrysler | Dodge | High Performance Transmissions | Performance Parts
Lots of good xmsn information on their blog.

From what I've read, the Long TruCool is about the best cooler there is. It is marketed under other names as well.
Good luck in your search. I'm interested to see how things work out for you.

[mstephens]

Thanks Top! I'll give them a call.

[ROBERTSUNRUS]

Hi, I personally don't believe in adding trans coolers; The cooler on your vehicle was designed to take care of your vehicle's needs. My Lincoln was rated to tow 8,900 lbs and my trailer is rated at 6,300 lbs, so no need to add anything. [load within factory specs]

But in your case, your tow vehicle was not designed to tow a 7,000 lb plus trailer. So you might very well need some extra help cooling your trans. I would, if I were you, look into another Chrysler product trans cooler like one for a Ram/Dodge 1500. I like the factory connections versus hose clamps. This might also be too much cooling at times therefore I would also consider a trans cooler thermostat.

[Jim Flower]

I have installed the Tru Cool transmission cooler on my last 4 Jeeps (excluding the diesel) and have found them to be 100% reliable! no issues, ever. I like the fact that they work only when needed since the flow of oil through them is controlled by the viscosity of the oil. So when it is cold, no flow, and when things start to heat up, the flow increases. Jim

[mstephens]

Originally Posted by Jim Flower

I have installed the Tru Cool transmission cooler on my last 4 Jeeps (excluding the diesel) and have found them to be 100% reliable! no issues, ever. I like the fact that they work only when needed since the flow of oil through them is controlled by the viscosity of the oil. So when it is cold, no flow, and when things start to heat up, the flow increases. Jim

Well, that's interesting. I've never heard of that. That's a couple votes for tru cool.

[mstephens]

What kinds of temperatures are people running at with loads? I generally ran about 185F in my Burb while towing. When it hit 219F on any occasion I pulled over immediately and let it cool to under 200 before proceeding.

Now with this 300, I am hitting 195 with no trailer. Hmmmm?

[SmokelessJoe]

mstephens, appreciate your intelligent posts.

Whichever secondary transmission cooler you decide on I think optimal placement is very important. Check out these installation instructions from a major performance manufacturer located near to you:

http://www.bulkpart.com/Merchant2/gr...all-Derale.pdf

Note particularly Diagram #2. If you place the cooler ahead of the air-stream as far as possible you will get optimal performance, I think.



I installed an additional cooler in my Sprinter after having warnings from a member here, Lewster.

You apparently know what your running temperatures are now. I could not know what the temperatures were BEFORE I installed a cooler because the Sprinter doesn't have a transmission temp gauge. Neither is is reported on my SCAN GAUGE because Mercedes won't release proprietary information to them. ( At least this was the case when I last checked with them about 2 years ago.)

So my point is that it is hard to know if the cooler is really effective unless you have base line figures.

I bought my cooler from The Sprinter Store in Oregon and had it installed according to their instructions. Later, after a full summer of pulling my trailer, I came across the Derale diagram.

My cooler is not installed optimally and I am going to check next spring to see if I can have it better located.

The Sprinter Store said that I didn't need a temperature gauge: ... " the transmission will run 20 degrees cooler".

I am therefore suspicious of their specific product. 20 degrees cooler than what?

I did install a transmission temperature gauge from Geno's Garage in Georgia, recommended by member Big Ed Moeller from South Carolina.

This shows that my truck is running in the 165-175 range alone and 185-190 pulling. So the trailer produces a 20 to 25 degree heat premium.

My own suspicion is that a lot of things effect transmission temperature: ambient temperature, wind direction and velocity, grade, etc.

I would add an auxiliary cooler if I where you but keep in mind all these points.

All the best,

Sergei

[SSquared]

Originally Posted by mstephens

What kinds of temperatures are people running at with loads? I generally ran about 185F in my Burb while towing. When it hit 219F on any occasion I pulled over immediately and let it cool to under 200 before proceeding.

Now with this 300, I am hitting 195 with no trailer. Hmmmm?

I see 190-210 when towing my 25 FB on the flat, with outside temp in the 90-100 degree range. When climbing mountains in Colorado, the tranny temp climbs steadily. I pull over and let it cool at 235. I don't have any solid basis for that 235 number.

I have a 2010 Yukon Denali 6.2 liter engine with 6 sp. transmission. The owner's manual doesn't say how hot is too hot, but it does say that the temp should be in the 160-200 degree range when checking the transmission fluid level. My independent mechanic says he found a reference that says the car will post the warning message at 266 degrees.

[subfan1]

Hi Mstephens, I'm following your adventure in downsizing closely. I'm glad someone from So Calif. is doing this this because I'm not so sure we can actually use sedans to tow our trailers in our hot summer environments and pulling long 6 to 7% grades for 10 to 15 miles to leave the greater Los Angeles area due to high temperatures. Thanks for doing this and I'm looking forward to your results.
Awhile ago you were looking for a Trans cooler for your Burb and I followed that thread because I own a Tahoe as well. What were your results regarding your Trans temp results if you changed out your Factory cooler?
Thanks again

[mstephens]

Originally Posted by subfan1

Hi Mstephens, I'm following your adventure in downsizing closely. I'm glad someone from So Calif. is doing this this because I'm not so sure we can actually use sedans to tow our trailers in our hot summer environments and pulling long 6 to 7% grades for 10 to 15 miles to leave the greater Los Angeles area due to high temperatures. Thanks for doing this and I'm looking forward to your results.
Awhile ago you were looking for a Trans cooler for your Burb and I followed that thread because I own a Tahoe as well. What were your results regarding your Trans temp results if you changed out your Factory cooler?
Thanks again

I held off doing a cooler on the Burb, because I had no confidence in any of my area mechanics to either A) recommend the right one; B) do quality work. Then after waiting the several months, I decided I would ultimately move on to a new TV, which is now the 300.

Once more, I am finding a lot of "mystery" about trans coolers from local mechanics. They just don't give me any confidence they know what they are talking about. I'm a bit flummoxed by that. People will say, sure we can put one in. Then I ask which one they would recommend, and they stumble around and essentially ask me which one I want!

I did see that diagram about placement and I really took that to heart, because the difference between 100% and 60% is no small matter!

I am running into a general problem: Finding real automotive experts. I stopped hot rodding whan I was 21. So it's been 45 years since I twisted a wrench. In the old days, you could find experts on everything. I know there were tons of guys in SoCal that could do any trick you could imagine with a car. Today, I just can't find anyone that knows jack squat about custom work. I am actually quite frustrated right now. This is off the tranny topic, but I will relate it anyway here. I called a local "RV Repair" guy - biggest ad in the phone book - to put my 7-way pigtail on the car and install my Prodigy 2 brake controller.
Guy: "Oh! Chrysler 300, that's a car! You're talking big bucks to do that kind of work."
Me: "Well, what do you mean big bucks?"
Guy: "Well, I have to figure all that out, it could take all day, I can't even give you an estimate. Bring it in and I will take a look."

Ok, I hung up and went on line. In 10 minutes I found explicit YouTubes on how to install the wiring harness on MY MODEL CAR! Then on the etrailer site, there were any number of instructions for connecting brake controllers. And this guy is going to charge me for "all day?"

Arghhhhh. Bad day here.

[gmw photos]

Originally Posted by mstephens

What kinds of temperatures are people running at with loads? I generally ran about 185F in my Burb while towing. When it hit 219F on any occasion I pulled over immediately and let it cool to under 200 before proceeding.

Now with this 300, I am hitting 195 with no trailer. Hmmmm?

Is there a Chrysler approved or recommended synthetic ATF ? Mobil ?

[MrUKToad]

We have an Andy T fitted Trans Cooler. His team supplied and installed it and I couldn't even tell you what make it is.

Unfortunately our Toyota transmission oil temperature sensor is only a simply good/bad switch so, unless I have it replaced with a proper temperature sensor and have a gauge fitted as well, I'm never going to know what the oil in the transmission is doing.

In the heat of the summer last year, and into a nasty headwind, the engine temperature touched 100C (212F) mark briefly when we were towing fully laden up the Niagara escarpment on the 401. As soon as we leveled out it dropped right back down again and I'm guessing that the transmission oil is doing something similar.

We've never seen the transmission oil temperature warning light come on so I guess we're working within the prescribed limits.

[slowmover]

Were your vehicle mine I'd be reserching the police-spec pieces for the Charger.

Been ten years now since I've done one, but I've always followed MOPAR procedure as to HD since 1968: Cooler located downstream of radiator cooler hard lines and filter added yet farther down before return to pan.

Used B&M Racing (LONG Mfg; bypasses fluid when cold) piece; located in line with mech. fan, some ways away from A/C condensor installed with steel strap.

Longest part of work was in construccting "harness" of hose/hard line that could be removed as a single piece. Used ADEL clamps to locate and zip ties in pairs to keep together. Very gentle bends on hose.

Used a small single pass DERALE cooler for power steering (same as MOPAR; HD & Police) in same way; also filter downstream (MAGNEFINE). One can cook PSF on a winter day in backing multiple times usually not enough airflow is the culprit.

To my knowledge there is no better ATF than SCHAEFFERS ATS.

.

[Wayward]

Originally Posted by slowmover

To my knowledge there is no better ATF than SCHAEFFERS ATS.

I do not know about better, but I have long been using Redline manual and automatic fluids exclusively in all our tow vehicles. Exceptional. No failures Their specs and testing match their claims of less molecular breakdown.

High temps and sheer forces from the gears and clutches breakdown the fluid. If the temps are within range, I suggest switching to quality fluid like Redline before upgrading the cooler, and see what happens to the temp when towing.

If you change the auto transmission fluid yourself, or have a shop do it, be certain that the torque converter fluid is drained properly. Otherwise you'll just be diluting the good stuff with the cheap stuff.

[mstephens]

Lots of good information here - thanks. I will certainly go to the synthetic ATF.

Just staring into the motor compartment, it appears the only place for another cooler (there is a very complicated oil cooler, and the AC condenser) would seen to be in the space between front grill and radiator stack. I assume these cooler can't be installed longitudinally, right?

My optimism about having the car ready this week is shot. The harnesses won't be here until Monday, and there is the whole transmission cooler thing to sort out yet.

[Wayward]

Originally Posted by mstephens

My trans temp without trailer at 70MPH is about 190F in 80F ambient conditions. I expect that to rise then to 210F in 100F weather, which is my neighborhood. That's before adding a trailer.

I do not necessarily think that your transmission temp would reflect a 20 degree increase in ambient temperature. Certainly the engine temp is thermostatically controlled.

One big difference I have noticed on my newest tow vehicle (2010 F250) is that the engine and transmission temperatures remain steady regardless of the outside temperature and trailer load. That leads me to believe the tranny cooler has more than sufficient heat transfer capacity and is thermostatically controlled.

That may be a feature to look for in a cooler.

[Wayward]

Originally Posted by mstephens

there is the whole transmission cooler thing to sort out yet.

You might consider a high grade fluid change and then take a test drive to monitor the transmission temperature without a cooler upgrade. As long as your temps do not go through the roof, the high performance fluid will give you protection.

If your current tranny cooler is integrated with your engine radiator, consider putting in Water Wetter. This significantly improves the heat transfer efficiency of your coolant.

[jcl]

No specific experience with the 300 here, but I have some thoughts on transmission coolers.

The last vehicle I had with an automatic transmission used a ZF transmission, which is also used by Chrysler in various platforms. My vehicle had a factory transmission heat exchanger, thermostatically controlled. No additional cooling was spec'd by the manufacturer up to the 6000 lb tow rating (which was 7700 lbs in Europe). When I read the service tech training documents on the transmission from the vehicle manufacturer, they described how the system utilized engine heat to bring the transmission fluid up to temperature more quickly, ie it heated as well as cooled, depending on the fluid temperature. I think that the cooling aspect is very important, but thinking about how most wear happens with cold fluid in the engine, it is likely similar in a transmission. You would want to avoid overcooling with an additional cooler, so as not to make the cold start up wear cycle extend over a longer period. That implies some sort of thermostatic control.

Not sure about your specific vehicle and which transmission it uses. But if you find out the transmission model, you can see where else it is used and those applications may have a cooler available for another platform. That helps you reduce the risk of excessive pressure drop across the cooler. Worth a try. I would also look into either police or taxi packages for that vehicle. Easiest option would be to use factory pieces where ever possible.

Finally, if we think about where the heat is coming from, on the highway it is from the torque converter and shifting. Seems obvious, but avoid any transmission hunting by using the manual mode. Learn where and when the torque converter goes into lock up mode (thus greatly reducing heat production) and figure out how to drive to maintain that lock up mode where ever possible when towing. Best way to avoid heat is not to produce it in the first place.

[mstephens]

Originally Posted by Wayward

I do not necessarily think that your transmission temp would reflect a 20 degree increase in ambient temperature. Certainly the engine temp is thermostatically controlled.

One big difference I have noticed on my newest tow vehicle (2010 F250) is that the engine and transmission temperatures remain steady regardless of the outside temperature and trailer load. That leads me to believe the tranny cooler has more than sufficient heat transfer capacity and is thermostatically controlled.

That may be a feature to look for in a cooler.

A few more comments about the temperature monitoring.

I drove 70 miles out at 59F outdoor temp and then 70 miles home later with the outdoor temp at 80F. The road out was a steady climb from 0 to 2600 feet, and then the reverse coming home.

On the outbound the temp climbed from 150F to 175F and stayed there for the last half hour.

On the way home it was ~195F all the way. From this, I gathered that the temp would pretty much rise with the ambient temp. Of course, it may not be linear, but at least between 59F and 80F it does look linear. 20F rise in ambient yielded a 20F rise in transmission. I am not sure I understand the relationship between engine temp and trans temp? How would they be coupled if there is no trans cooler? Mysterious to me.

Today, just driving around town - stop and go - it pretty much stayed at 199F. The ambient was around 68F. Seems high to me.

I stopped at Chrysler dealer service to ask the price of a factory cooler. Oddly, they said MoPar did not make a unit for this car(???) and an aftermarket would be $180 parts + $345 labor. No brand was given. Talking to service bay agents is not very satisfying, to say the least. They are really clerks, not car buffs. So, I could get no useful advice about cooling, or fluids. Today I will try to connect with some sort of corporate "tech support."

I'll also be screening transmission shops by phone to see if anyone sounds knowledgeable about such things as coolers.