B&M tranny cooler questions

[piecesparts]

I have been reading different posts made on this web about external tranny coolers. All were installed to eliminate the infamous Strawberry milkshake issue. Some individuals stated that after they installed their tranny cooler and temp gauge, they noted that the tranny oil temp would reach the max temp on the gauge while in traffic. They thought that they should put in a larger tranny cooler. So here are the questions: What do you have for a cooler and what experiences have you noted with that cooler? If you have a temp gauge did you note any issues of overheating with the external cooler?

Many installed the smaller of the following three coolers.
#70268 13,000 BTU
#70264 14,400 BTU
#70266 20,500 BTU

The B&M information for these coolers states that the first two (the smaller sizes) have a bypass capability for colder fluids. That is a little different and I haven't got that one figured yet. If it bypasses when it is cold, then it will do so when the fluid is warmer, thus defeating some of the cooling capacity.

The larger one does not have a bypass capability, so there could be some issue with fluid movement capability on a really cold day. Basically that is when I would want to drive the T4R.

Open for thoughts on this.

 

[Jaketino]

I'm about to pull the trigger on buying a 14,000 btu one. Curious if I would need the bigger one or not.

 

[19963.4lsr5]

There is a optimum temp range for the trans fluid. The bypass in the two smaller coolers ensures the oil stays at or above what BM considers optimum.

I personally think 160-180 is a good temp for the trans fluid.

But in the winter my Saturn never gets out of the low 130's. So maybe a range of 130 to 180 would be accurate.

If I had a spare thran pan I'd think about putting a water in oil sensor from a diesel fuel filter to see if that will catch the milkshake. It be easy to test I guess.

 

[vipergrhd]

My 2 pennies

First thing never run an aux.cooler only unless it's the size of the radiator,liquid cooler is more efficient and it is better if you add an aux. cooler.In 25 years that i have been wrenching i have never seen yet a manufacturer (correct me if i'm wrong here) that is running just an air to liquid cooler,if you are worried about milkshake replace your radiator and add the proper coolant/distilled water mixture and you won't have the milkshake issue then you can add your B&M cooler if you like.

 

[Nelsonmd]

Don't overthink the size. Both the 768 and the 764 have been used widely and are fine.

The reason the tranny hits high temp in traffic is because no air is flowing through the cooler, so there is no cooling effect. The larger coolers won't make a difference in this regard; no air flow is no air flow, regardless of the cooler size.

Get either of the smaller ones and you will be fine. I think the only reason to specifically go with the larger cooler would be if you tow heavy loads frequently, otherwise the 768 is just fine.

 

[01thunder]

i've been running a cooler out of an explorer for 6 months now without problems. cost me $17 at a pull it yard. no need for a bm one. the tundra had coolers as well. those work as well.

 

[snivilous]

First thing never run an aux.cooler only unless it's the size of the radiator,liquid cooler is more efficient and it is better if you add an aux. cooler.In 25 years that i have been wrenching i have never seen yet a manufacturer (correct me if i'm wrong here) that is running just an air to liquid cooler,if you are worried about milkshake replace your radiator and add the proper coolant/distilled water mixture and you won't have the milkshake issue then you can add your B&M cooler if you like.

Can you explain this? I'm not quite following your logic. Ultimately most land based cooling systems use air to get rid of the heat, granted they may have a liquid system to quickly extract heat from the source (engine, cpu, etc.) but they still need radiators which dump the heat from that liquid into the air. What other kind of cooling system would you use on a vehicle, and why would that make you not want to run an external cooler/radiator for the tranny?

 

[UTEP]

First thing never run an aux.cooler only unless it's the size of the radiator,liquid cooler is more efficient and it is better if you add an aux. cooler.In 25 years that i have been wrenching i have never seen yet a manufacturer (correct me if i'm wrong here) that is running just an air to liquid cooler,if you are worried about milkshake replace your radiator and add the proper coolant/distilled water mixture and you won't have the milkshake issue then you can add your B&M cooler if you like.

I love this topic!

It seems most experienced mechanics suggest running the B&M (or similar) in series with the radiator and replacing the radiator to avoid pink milkshakes. Manufactuers rate their coolers based on this installation. So if you want 20k btu cooling you must install in series..

That said Most 4runner guys heres here who I have come to respect as excellent 4runner mechanics suggest running the auxiliary ATF cooler solo; no radiator cooling at all!

I replaced the radiator and run a B&M 70268 in series. I have noticed this winter the trans already takes a while to get comfortable with 40°-50° so I'm not sure if I want a cooler that is more "efficient". This is a cooler with the bypass and the next size up has no bypass. Not bad in summer and maybe ok in winter but like I said my trans likes warmer T's.

Happy New Year

uTep

 

[piecesparts]

Now, you all can see why I started this post. I work in the nuclear industry and liquid to air coolers are NOT the norm. Liquid to liquid is the most efficient, however there is also the issue of radioactive contamination getting out to the public in my world, so the buffer system between the radioactive liquid and the lake water is a must. I agree that the series lineup of coolers is the best and that is how my show truck is set up, but this forum and others go for the separate cooler to eliminate the cross contamination of the tranny and radiator.

Apparently the factory radiator is a little weak in design. My T4R radiator was replaced a very few thousand miles ago, due to a deer hit, so it is NOT the original radiator, but it is a Toyota radiator none the less.

 

[HiluxSurf SSR-G]

TRD recommends that the TRD atf cooler be used with the radiator and be located after the radiator. I had this setup previously but about two years back, I decided to bypass the radiator and installed a B&M 70264 after the TRD atf cooler. That way, the strawberry milkshake risk was eliminated.
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[LittleCaesar]

I use the 70264 in line with the ATF exchanger in the radiator for 4 years with no problems (the radiator is a Koyo).

 

[19963.4lsr5]

i've been running a cooler out of an explorer for 6 months now without problems. cost me $17 at a pull it yard. no need for a bm one. the tundra had coolers as well. those work as well.

That's exactly what mine was off of.

I also got a larger one off a 1ton Chevy van.

I had a trans cooler from a newer dodge Durango. I carried it to a 4runner in the boneyard to see if I could find a way to mount it. It was too long. It was too long. It would have been nice. It was 6"-8" tall and around 10" longer than the rad and condenser.

 

[Robb235]

It seems most experienced mechanics suggest running the B&M (or similar) in series with the radiator and replacing the radiator to avoid pink milkshakes. Manufactuers rate their coolers based on this installation. So if you want 20k btu cooling you must install in series..

You're saying if B&M rates the 70264 cooler at 14,400 BTUs, then I have to run it in series with the stock cooler in order to reject those 14,400 BTUs? I've never heard this before. Do you have anything to back this up?

I don't understand how B&M could rate how many BTUs their coolers can reject if it's based on something well outside of their control. How does B&M know how many BTUs my stock radiator-mounted trans cooler can shed? Or what if I'm installing B&M's cooler on a vehicle that didn't come with a trans cooler, then what?

 

[UTEP]

You're saying if B&M rates the 70264 cooler at 14,400 BTUs, then I have to run it in series with the stock cooler in order to reject those 14,400 BTUs? I've never heard this before. Do you have anything to back this up?

I don't understand how B&M could rate how many BTUs their coolers can reject if it's based on something well outside of their control. How does B&M know how many BTUs my stock radiator-mounted trans cooler can shed? Or what if I'm installing B&M's cooler on a vehicle that didn't come with a trans cooler, then what?

Hi,

From B&M:
"If the radiator in your vehicle does not have provision for a transmission cooler you must use a larger fluid cooler, than you would normally consider, for the vehicle. Typically the smallest cooler you should consider when not using the radiator provision would be the B&M #70266 or #70272 Universal SuperCooler."

Perhaps the instructions were more concise about the btu's but the above indicates this to me. I couldn't judge a btu in real life so it's just a measuring stick.

At any rate your choices will be in series with radiator or not. If not I'd suggest a larger cooler, perhaps with a fan depending on the extremes you anticipate.

Once again LOTS of guys here are running the 70268 bypassing the radiator with no problems…..
I was not comfortable with this set up and would opt for a larger cooler if I decide to by-pass.

I started a thread a while back that has some good info despite my green horn approach. It answered my questions…


http://www.toyota-4runner.org/3rd-g...ive-guide-radiators-transmission-coolers.html

HTH

Utep

 

[Robb235]

Hi,

From B&M:
"If the radiator in your vehicle does not have provision for a transmission cooler you must use a larger fluid cooler, than you would normally consider, for the vehicle. Typically the smallest cooler you should consider when not using the radiator provision would be the B&M #70266 or #70272 Universal SuperCooler."

No where does that indicate to me that to achieve the rated BTU rejection (14,400 BTUs in the case of the 70264) that I have to run in series with the radiator. Telling me that I would have to run a larger cooler than normal if I'm bypassing the rad is a "no sh!t" type of disclaimer.

 

[AlphaEcho2k5]

My experience with the Tru Cool 4590 has been positive. I have my radiator bypassed and even on the coldest days (-30f) sure it took a little to warm up but, I was letting the truck warm up anyway before driving. My temps stay around 100-120 according to my Scan Gauge and the highest I've seen is 170 in 3-4 hour off-road trip.

 

[piecesparts]

Without knowing what the capacity of the installed cooler in the radiator removes for BTUs, it cannot be said what size external cooler would be needed. The transfer of heat from the tranny to a water with a temperature around 125 degrees, means that the transfer cannot be as much as the transfer delta T from a 180 oil to a 70 degree ambient air. However, the transfer of heat ratings that B&M gives would be without any other interactions involved, so if they state capable of 14,000 BTUs, then I am sure they mean that much heat can be transferred if the conditions are just right.

The speed of the oil flow, the speed of the air flow, and the delta T between the two is what has to be known to make this calculation.

 

[Nelsonmd]

Jeez guys, you're overthinking it... Don't try to make this a heat transfer homework problem. Lots of guys here have a tranny temp display and can watch the tranny temps. Both the 768 and 764 show good tranny temperatures pretty much year round (the specifics are out there). You can try to solve the theoretical problem all you want, but you already have the data, so what's the point? The musings about air vs liquid and whether 14400 is enough, or if it's really 14400 and is that enough are meaningless if they don't agree with the data that is already out there.

And BTW, Viper is incorrect, lots of vehicle came from the factory with liquid to air tranny cooling systems. It's been done for many many many years. Routing the tranny coolant to the radiator can give you the added functionality of warming the tranny fluid, but that is not really going to happen unless you leave it idling long enough for the engine to warm up past the thermostat's trigger temp, warm the radiator then finally start warming the tranny fluid.

And as far as cooling, you can say all you want about transfer efficiency of liquid to liquid systems, but they will only reject heat to a body that is colder than they are, meaning when your engine is running at the standard 191C, then your tranny is only going to be able to reject heat to 191C. Most all the guys running the 768 (smaller) cooler in bypass report well under 191C for the running temp on their tranny. And mine doesn't really get below 120-140C even in the winter on the highway when the cooling it as it's best.

If your radiator was just replaced, then don't bother with a tranny cooler unless you are towing alot or off roading alot. And don't compare a consumer vehicle engine to a nuclear power plant cooling system, they are COMPLETELY different. The principle is the same, but you can't draw any conclusions about what is the best vehicle radiator based on what is used in nuclear power plants.

 

[Robb235]

Jeez guys, you're overthinking it... Don't try to make this a heat transfer homework problem. Lots of guys here have a tranny temp display and can watch the tranny temps. Both the 768 and 764 show good tranny temperatures pretty much year round (the specifics are out there). You can try to solve the theoretical problem all you want, but you already have the data, so what's the point? The musings about air vs liquid and whether 14400 is enough, or if it's really 14400 and is that enough are meaningless if they don't agree with the data that is already out there.

Spot on.

Without being able to monitor trans temps myself, I was hesitent to reference other people's temp readouts. But yeah, from seeing other members posting their trans temp finding when bypassing the radiator, I think it's pretty much been proven that the transmission is better than stock when bypassed with either the 768 or 764.

 

[Swimmerboy2112]

My .02

I went with the larger of the B&M coolers for a few reasons;

-I tow with my 4Runner occasionally.
-It is supercharged which i'm sure puts more stress on the trans.

I ran the trans cooler separate from the radiator system for a few reasons;

-Running the trans cooler in line with the rad will do NOTHING to stop the milkshake.
-Running the trans fluid through the radiator does nothing aside from warm up the fluid before it makes its way to the trans cooler.