Tranny cooler sufficient enough for AZ summer driving

[Stgo2019]

An external cooler is not necessarily needed in AZ.

I replaced my radiator at 115K, just for the hell of it.

No external cooler and in 120 degree heat, I have never seen water temps above 197, per my scan gauge.

Now, if you don't want to replace your radiator and want to avoid the pink milkshake. Go for it.

Otherwise a new rad is more than sufficient.

 

[EvilMole]

An external cooler is not necessarily needed in AZ.

I replaced my radiator at 115K, just for the hell of it.

No external cooler and in 120 degree heat, I have never seen water temps above 197, per my scan gauge.

Now, if you don't want to replace your radiator and want to avoid the pink milkshake. Go for it.

Otherwise a new rad is more than sufficient.

I'm leaning more towards a new radiator and skipping the bypass. I'm only slightly concerned about pink milkshake because of the age of my current radiator. My radiator fluid is fairly clean so I may be concerned about nothing, but replacing the radiator is cheap insurance I guess.

I could just throw an external cooler on now and new radiator when needed, but this leads back to my original question. I do a lot of stop and go driving along with long idling periods when picking the kiddos up from school.

 

[willbgood]

Pink milk shake= new trans + radiater =well over 1000 bucks and almost double if you cannot do it yourself, because you either do not have no skills, tools or on the road.

trans cooler + fan+ plus thermostat+ gauge= 250 bucks or so, and piece of mind.

If off roading, a small puncture, or broken seam, could destroy your trans before you reach pavement...

 

[19963.4lsr5]

The preferred trans temp my the auto manufactures is 180. I like 120-160 my self. Anything too cold effects the shift schedule and it holds gears or won't allow overdrive and lockup.

 

[turbodudey2]

The preferred trans temp my the auto manufactures is 180. I like 120-160 my self. Anything too cold effects the shift schedule and it holds gears or won't allow overdrive and lockup.

I agree. I'm pretty happy with the 140 to 160 degree range that I see every day.

There's really no reason to ever try adding heat to the trans fluid loop. Weather that is from the heat exchanger in the radiator or otherwise. And over-cooling isn't an issue either since it's a self correcting system. I'd much rather have the torque converter hold off lock up for the extra 6 seconds after a cold start in the morning, than be a regular visitor of the 200+ degree range which starts shortening fluid life.

Granted I have a big filter on mine, but the last 30,000 mile drain and fill couldn't tell the difference between new fluid and old. And all of those miles were in the 115+ Arizona goodness.

 

[cp99sr5]

In northern California, tow a small boat so I went with a by passed B&M 70266, it does not sit flush with the AC condensor but about a half inch off. was seeing temps from 140 to 180 with external temps in the 70's to 100's.

Then I replaced the radiator with a new one so I went in line with the fluid running through the radiator and then through the cooler before returning to the tranny. Disclaimer - I am not proposing that inline or bypassing is better or worse, its just what I did!

I went on a recent trip pretty well loaded up, outside temps in the high 80's at an elevation of 8000 feet plus. the highest temp I saw pulling up long passes was 197 for about 15 minutes max otherwise about 150 to 160 average. I think the larger cooler does a great job weather or not you bypass, my 2 cents.

 

[Stgo2019]

I'm leaning more towards a new radiator and skipping the bypass. I'm only slightly concerned about pink milkshake because of the age of my current radiator. My radiator fluid is fairly clean so I may be concerned about nothing, but replacing the radiator is cheap insurance I guess.

I could just throw an external cooler on now and new radiator when needed, but this leads back to my original question. I do a lot of stop and go driving along with long idling periods when picking the kiddos up from school.

My kids fall asleep in the car when we're out running errands on weekends. I stay in the car while my wife goes into Target to do the shopping. I've sat there in 110+ heat with the AC running for up to 45 minutes and never seen water temps above 193.

I say water temps because I have not installed a trans temp gauge, but since the trans fluid is cooled by the radiator, and my truck is nowhere near overheating, I feel that the trans temps are within spec.

Toyota has had an Arizona Proving Ground just outside of Phoenix since 2003. I'm confident that Toyota is fully aware of the potential temps their vehicles will encounter and that they have designed the cooling system accordingly.

Toyota's North American Proving Ground Celebrates 20 Years | Toyota

Feature: Toyota's Arizona Proving Grounds - Autos.ca

 

[willbgood]

I have duel inline senders hooked up. One is installed as close as I could get it to the trans send line and the other as close as I could get to the return line after the cooler.

In day to day driving, I typically see a 15 degree difference between the two with the send line never reading above 165F.

I don't know what the optimum operating temp is for the tranny, but since installing the cooler and gauge in the spring, I have never witness temps going over 165F.

I have not done any towing or wheeling yet though and aside from lift and 33" tires, I am not carrying any extra weight (stock bumpers, no gear).

Again though, I'm in Canada. The real test will be in the winter. A lot of people have been making me nervous saying that the trans fluid will remain too cool because I bypassed. I have a hard time believing this will affect me since I've never heard of a trans failure because of that, but we'll see.

The 70268 has a lowtemp bypass which should prevent this.

Can you detail this out? Do you use two gauges?

 

[floatingkiwi]

I don't know what the optimum operating temp is for the tranny, but since installing the cooler and gauge in the spring, I have never witness temps going over 165F.

50-80 deg C or 122-176F

 

[SpidermanGeek]

Can you detail this out? Do you use two gauges?

No, single gauge with senders connected to an ON/ON toggle switch.

I normally just leave the send line reading on. If temps get hotter, then I'll do a quick flip to the return line temp to see how well the cooler is working.

Knowing the temp of the fluid that the tranny is ejecting as well as the temp of the fluid that's going back into the tranny let's me know that everything is working as it should.

 

[SpidermanGeek]

My kids fall asleep in the car when we're out running errands on weekends. I stay in the car while my wife goes into Target to do the shopping. I've sat there in 110+ heat with the AC running for up to 45 minutes and never seen water temps above 193.

I say water temps because I have not installed a trans temp gauge, but since the trans fluid is cooled by the radiator, and my truck is nowhere near overheating, I feel that the trans temps are within spec.

Toyota has had an Arizona Proving Ground just outside of Phoenix since 2003. I'm confident that Toyota is fully aware of the potential temps their vehicles will encounter and that they have designed the cooling system accordingly.

Toyota's North American Proving Ground Celebrates 20 Years | Toyota

Feature: Toyota's Arizona Proving Grounds - Autos.ca

Well in this particular situation your trans temps would probably be within specs even if there was no cooling system for the fluid since it's basically not doing any work at all while your parked at Target. lol.

 

[willbgood]

No, single gauge with senders connected to an ON/ON toggle switch.

I normally just leave the send line reading on. If temps get hotter, then I'll do a quick flip to the return line temp to see how well the cooler is working.

Knowing the temp of the fluid that the tranny is ejecting as well as the temp of the fluid that's going back into the tranny let's me know that everything is working as it should.

What sending units do you use?

 

[Stgo2019]

Well in this particular situation your trans temps would probably be within specs even if there was no cooling system for the fluid since it's basically not doing any work at all while your parked at Target. lol.

Good point,
So by that rationale, sitting in stop and go traffic the transmission wouldn't be working very hard and would not be in danger of overheating?

I guess my main point is that; in normal driving, irregardless of ambient temperature, our trucks cooling systems (engine/transmission) are more than adequate to keep our transmission and engines from imploding.

After reading dozens external cooler and pink milk shake threads. I have come to the conclusion that most people install the external cooler solely to prevent the milkshake, thinking that the Toyota design is flawed and in need of improvement. Whereas the actual cause of the milkshake has nothing to do with the actual efficiency of cooling the trans fluid, and more to do with the radiator maintenance, or lack there of, by the previous owner/s.

Am I way off base?

Matt

 

[willbgood]

Good point,
So by that rationale, sitting in stop and go traffic the transmission wouldn't be working very hard and would not be in danger of overheating?

I guess my main point is that; in normal driving, irregardless of ambient temperature, our trucks cooling systems (engine/transmission) are more than adequate to keep our transmission and engines from imploding.

After reading dozens external cooler and pink milk shake threads. I have come to the conclusion that most people install the external cooler solely to prevent the milkshake, thinking that the Toyota design is flawed and in need of improvement. Whereas the actual cause of the milkshake has nothing to do with the actual efficiency of cooling the trans fluid, and more to do with the radiator maintenance, or lack there of, by the previous owner/s.

Am I way off base?

Matt

I don't think you are, but their is another rational that I used as well. My thinking was that if for some reason I had radiator damage, if it included the water system and the trans fluid sections together, I would be screwed if I was 100 miles from no where. Whereas, if the systems are separate, I can do an expedient repair and limp to a place where I can get parts and make a repair without the possibility of the fluids mixing...I know the odds are remote that this type of damage would occur, but I am a remote odds thinking kind of guy...

 

[SpidermanGeek]

What sending units do you use?

I have the AutoMeter 2640 Short Sweep Trans Temp Gauge (which comes with 1 sender) and I bought an extra matching sender (Autometer 2258).

 

[SpidermanGeek]

I don't think you are, but their is another rational that I used as well. My thinking was that if for some reason I had radiator damage, if it included the water system and the trans fluid sections together, I would be screwed if I was 100 miles from no where. Whereas, if the systems are separate, I can do an expedient repair and limp to a place where I can get parts and make a repair without the possibility of the fluids mixing...I know the odds are remote that this type of damage would occur, but I am a remote odds thinking kind of guy...

This was part of my reasoning for going bypass external cooler only. Just keeping the different systems independant of each other helps prevent cascading problems if 1 of those systems fail.

 

[SpidermanGeek]

Good point,
So by that rationale, sitting in stop and go traffic the transmission wouldn't be working very hard and would not be in danger of overheating?

The potential for overheating is higher because in stop and go traffic, the transmission is in Drive, so it's engaged and in a constant state of "spool up/spool down-push/stop/hold". So although the load might be minimal, the transmission is still tasked with a lot of activity in stop and go traffic.

 

[cashmoney]

If you are in stop and go your torque converter is just chopping up fluid and building heat with minimal air flow over the radiator. In neutral the fluid is routed differently internally in the transmission and through the converter but the pump is still turning inside the transmission and pumping fluid through the coolers and while even though there is still minimal air flow you don't have the converter spinning up the fluid and building heat so it's not a problem. Matter of fact, if you'll read your owners manual it'll tell you to put the vehicle in neutral and increase the rpm's to increase flow and help drop temperatures. Once the converter locks up (usually in 3rd gear and you might even feel what seems like a shift but it's not) temps will drop as well because now the engine and transmission are coupled together as one unit just like a standard clutch so you don't have the converter shredding the fluid and heating it up. Your fluid will heat up in stop and go traffic and I've seen trans temps at 220* sitting in traffic with completely stock vehicles so I'm not concerned at all with trans temps at 200* during normal driving. 220* stagnant sitting in traffic is different than 220* under full load when the clutches and steels are really needing the cooling and lubricity.

 

[JohnJMonroe]

I use the TrueCool 4589. It's almost too big to mount. My 97 puppy hauler thread has more info.

I think thats the one I have. I have it running through the radiator, then through the external cooler. Honestly, temps are lower that I'd like. I've never seen it go above about 190 even in the Tucson summer going to up Mt Lemon or beating on it wheeling.

That cooler is a beast.

 

[19963.4lsr5]

I think thats the one I have. I have it running through the radiator, then through the external cooler. Honestly, temps are lower that I'd like. I've never seen it go above about 190 even in the Tucson summer going to up Mt Lemon or beating on it wheeling.



That cooler is a beast.

Yep, I think 130 was the highest in winter without me power braking it to see how hot I could get it. I checked summer a few times and oil pan temp was less than 160 every time.