Transmission cooler: to by-pass the radiator or not to by-pass it

[ajonesnv]

I'm looking on Craig's list for someone parting out a 94 to 98 dodge ram with the cummins.

They have a external heat exchanger under the turbo. Coolant on one side and trans fluid on the other. And it's pretty large.

I was thinking of putting it in series with the existing engine oil coolers coolant lines or tapping off the heater core lines Pryor to the cutoff valve.

I'm thinking the engine oil cooler line going to the water pump housing is a return. I could tee into that as well for the return and supply it from the upper heater line.

Those heat exchangers don't fail. Unlike the ones on the 98 1/2 and newer engines where they changed location and design.

Im thinking you have waaaay over thought this. Large independent trans coolers or a new radiator with a moderate trans cooler has been proven to keep temps where they need to be. The point is to avoid the milkshake.

I personally bypassed the radiator and installed a large cooler and thermal bypass (to avoid too low of temps) http://www.toyota-4runner.org/3rd-gen-t4rs/114385-radiator-bypass.html. But many have just replaced the radiator and added a cooler equivalent to the TRD sized one.

And if you are planning on using the oil cooler to cool trans oil you won't, it will be too hot.

 

[19963.4lsr5]

I was going to use it in place of the cooler in the rad. And a external also.

I'm pretty sure the rad I have is recently replaced though.

 

[Drcoffee]

Then why is there an existing oil cooler if it will make engine oil too hot. Or are you saying it will be too hot to cool trans oil?

Thank you. Thats what I was inferring. The 4runner radiator is fairly large. The trans cooler is fairly small. For any kind of abuse the external cooler will help normalize the trans fluid temps after the radiator.

 

[BrianSD_42]

I want to put a little more data into this thread, since it's still alive.

Having my radiator bypassed for about 4 months now (on my current 4Runner), I have temperature numbers for several months worth of stock cooler, and several months worth of bypassed cooling with the 70264.

The factory cooler does maintain a smaller window of temperature range. For example, on a day like today (a beautiful 65 degree day), the factory cooler would keep the transmission temperature between 148 and 160 during normal driving. That's a 12 degree window, give or take a degree or two.

The aftermarket cooler, bypassing the radiator maintains transmission temps of about 140-162. That's a 22 degree window.

In all seriousness, what was gained?

I already replaced my radiator so based on your data why would I add a coolant bypass, what would be gained?

I am leaning towards DR Coffee's argument of adding a cooler in-line with my recently replaced stock radiator. Mainly because I am a bit paranoid about higher temps in my trans as I cannot read those temps in my 97 so I have no idea if it is hot or normal.

 

[the great him]

the factory trans "cooler" is really not a cooler at all, its more of a regulator, it helps regulate temps, not cool them. it will bring them up to the SOT faster and help keep it at that point -mind you its close to 190*. but if your motor over heats then so will your trans... so instead of cooking just a motor you have cooked a motor and a trans(go big or go home i guess...). if you start to over heat your trans there is not enough capacity in that small "cooler" that it will cool anything, even if you put a external cooler on, but yet keep it running through the stock "cooler" it will pretty much negate most of its cooling abilities. -not to mention you still run the risk of the pink milkshake(the main reason for this mod). running a stand-alone single larger single cooler for a stock rig(dual stand-alones or a larger cooler with a electric fan for modded rigs) is your best bet. it will keep temps at lower temps(well above 140* -and well into safe operation temps), and prolong the life of your ATF.

as far as the temp gauge, and distractions are concerned, i think this is a fear that is not really a warranted fear. do you constantly stare at your RPMs or MPH or fuel gauge, or coolant temps? how about your stereo? then why would you be watching your trans temp gauge. the only time i look at it is to check it when i am going up a hill or under prolonged loads -say towing, and even at that im just glancing at the gauge, not staring at it. gauges are designed to be scanned not watched. i can easily check my gauge while checking my mirrors or looking around at the road and my surroundings. i have only ever stared at my gauge when doing diagnostics, and work on the motor or trans, and atempting to get it hot or putting heavy loads on things and all of that has been at either very slow(crawling) to stand still speeds, say like in a shop or trying to pull someone or something out. at which point i dont need to be looking at the road ahead all that much. after a few days you will get used to it being there and not even notice it, it will become just like the rest of the gauges and dash, just cooler looking.

 

[pdx650]

In all seriousness, what was gained?

I already replaced my radiator so based on your data why would I add a coolant bypass, what would be gained?

I am leaning towards DR Coffee's argument of adding a cooler in-line with my recently replaced stock radiator. Mainly because I am a bit paranoid about higher temps in my trans as I cannot read those temps in my 97 so I have no idea if it is hot or normal.

Just add an autometer gauge and temp sensorlike I did.Posted in 'What did you do to your 4runner....'

 

[Drcoffee]

The transmission will generate most of its heat when the torque converter is unlocked, which is most of the time you are driving in traffic. You can tell if the TC is locked by taking your foot off the gas. If you feel a jerk or slow down then the TC is locked. If you let off the gas and the rpms fall and your truck just coasts, the TC is unlocked. Where am i going with this? Much of the time you are driving except for hwy, the TC is unlocked and creating heat. The radiator modulates the trans temp, but under load, its inadequate. With my b&m cooler in series, pulling a trailer at 65 mph (TC locked) my temp is 155-160*. Without the trailer i run between 120-135*. That is really the sweet spot for the tranny to operate. Why go thru re-engineering the trans cooler, finding the best combination of size and number of coolers for all seasons. when a simple addition to a new radiator is all you need. Can you imagine living in CO where temperature swings can range from -30* to 110*. You will still run hot on hot days and too cool on cold days. I have better thing to do on a cold-ass day than slipping a piece of cardboard in front of a cooler to block air flow.

 

[quicksilvr]

I guess my deal is this:


In 3 years of driving 4runners with auxillary coolers and the factory cooler bypassed, I have yet to encounter a a single situation where the transmission cooling was inadequate OR too aggressive.

Conclusion: no chance for a milkshake, and it still works great all the time. Win.

 

[Drcoffee]

Magnefine filter results after 30,000

Lets take a tangent for a minute. On all my vehicles, I use a Magnefine inline filter. I finally reached 30,000 miles and replaced it. I made a youtube video of the contents of the filter that came from my 2008 Sienna. Its well worth watching.

30,000 mile Magnefine filter change - YouTube

* just some background on the video. Some folks on another forum believe the trans filter is an effective filter.

 

[the great him]

Lets take a tangent for a minute. On all my vehicles, I use a Magnefine inline filter. I finally reached 30,000 miles and replaced it. I made a youtube video of the contents of the filter that came from my 2008 Sienna. Its well worth watching.

30,000 mile Magnefine filter change - YouTube

* just some background on the video. Some folks on another forum believe the trans filter is an effective filter.

There is a reason I run two of them... One before my coolers and one after my coolers... And I change them both every 15k miles... Yeah I'm paranoid I know

 

[segafan1989]

I guess my deal is this:


In 3 years of driving 4runners with auxillary coolers and the factory cooler bypassed, I have yet to encounter a a single situation where the transmission cooling was inadequate OR too aggressive.

Conclusion: no chance for a milkshake, and it still works great all the time. Win.

^^FACT! Milkshakes are only cool when they come in a cup and a nice big straw...other than that, bad juju.

 

[redstar]

You mean heat sink? Are you an expert on this sort of thing? You come off as one.

Using my own data, I can comfortable disagree that a small cooler is insufficient for cooling this transmission on all but the hottest days or under extreme loads.

Where's your data?

Ironically, "heat-sync" is quite apt... lol

 

[Mint]

Sorry to bring this back from the dead - but another confused noob here.

Just picked up at 02 Limited 4WD 4runner last week with 130k miles on it.

Original radiator is there but the fluid in it looks perfectly clear (although its a clear yellowish color)

None-the-less I want to take care of this truck as I plan to keep it till it explodes

I'll be towing pretty regularly with it and for long distances over many long hills on the freeways around southern california. Trailer will weigh only around 1600 lbs though. Other than towing it will be used as a camping vehicle.

I'm looking at radiators, primarily the spectra one autozone offers a lifetime warranty on AND adding BM 70264 but I'm confused.

Series with the radiator or bypass? This thread seems to go all over the place.

 

[redstar]

I would bypass, as that would eliminate the milkshake. But, that has its downsides. You will need a bigger cooler. Your engine coolant will not warm up your tranny fluid(a little rough on the tranny in the cold). You might over-cool the fluid(optimal is 180F) so you might consider a bypass thermostat.

I went with a large hayden cooler + a derale bypass thermostat.

 

[acr_ted]

I would bypass, as that would eliminate the milkshake. But, that has its downsides. You will need a bigger cooler. Your engine coolant will not warm up your tranny fluid(a little rough on the tranny in the cold). You might over-cool the fluid(optimal is 180F) so you might consider a bypass thermostat.

I went with a large hayden cooler + a derale bypass thermostat. Looking at getting an in-line heater for the winter. Im in northern Ontario for the winters :S

Where in Northern Ontario? I used to live in Hawk Junction, near Wawa, north of Sault Ste Marie. I still remember one winter when it was at least -60, but it might have been colder. The mercury was all huddled up in the bottom of the thermometer!

Ted

 

[ajonesnv]

Looking at getting an in-line heater for the winter. Im in northern Ontario for the winters :S

I have never seen an in-line heater for oil lines. Can you post a link to what your talking about? Not that I would ever need one, but sounds kinda cool.

You keep saying this, but can you back it up with facts? Not trying to be a dyck, it's just that you seem very confident.

Your most likely not going to get any sort of response if you randomly throw in a question that does not have a reference quote or content in the question that references a past post.

 

[Mint]

I would bypass, as that would eliminate the milkshake. But, that has its downsides. You will need a bigger cooler. Your engine coolant will not warm up your tranny fluid(a little rough on the tranny in the cold). You might over-cool the fluid(optimal is 180F) so you might consider a bypass thermostat.



I went with a large hayden cooler + a derale bypass thermostat. Looking at getting an in-line heater for the winter. Im in northern Ontario for the winters :S

The 70264 has some sort of mechanical bypass based on fluid viscosity.

You don't think the 14400 btu of cooling it will provide will be sufficient?

I realize the point of the bypass is to reduce SMOD but from what I've read you can replace the radiator or put in a cooler to prevent it. I'm doing both the cooler more for towing. Will the cooler alone be sufficient if I do bypass?

 

[ajonesnv]

The 70264 has some sort of mechanical bypass based on fluid viscosity.

You don't think the 14400 btu of cooling it will provide will be sufficient?

I realize the point of the bypass is to reduce SMOD but from what I've read you can replace the radiator or put in a cooler to prevent it. I'm doing both the cooler more for towing. Will the cooler alone be sufficient if I do bypass?

A new radiator may or may not hold up, thats the big issue, no one knows how long you have if/or when the milkshake will/might happen.

I would recommend fitting the largest possible in the space, even though what your looking at may be suffice. I fit an 11x8x1.5 cooler without a built in bypass because I added a legit thermal bypass to the line, I don't trust the internal ones enough considering added peace of mind the external bypass brings. One of the added benefits of the external bypass is knowing that it has a rated operating range and that cold fluid is not being sent to the cooler.

Bear in mind, most of everything you hear on this subject is either theory or experience practiced under specific conditions, so no one person can say with all certainty what you need. What I have is sufficient, but could be VERY likely too much for another that lives in the north.

Paying attention to the oil temps is a major key in this process...I don't feel its a project you can install and forget about, you need to be able to monitor your temps and make driving adjustments as you see the data.

 

[redstar]

The 70264 has some sort of mechanical bypass based on fluid viscosity.

You don't think the 14400 btu of cooling it will provide will be sufficient?

I realize the point of the bypass is to reduce SMOD but from what I've read you can replace the radiator or put in a cooler to prevent it. I'm doing both the cooler more for towing. Will the cooler alone be sufficient if I do bypass?

Im sorry, by "bigger cooler" I simply meant bigger than if you put a cooler in series with your rad.

Yeah, some of the B&M models have that.

Thats the thing, I spent a stupid amount of time searching through forums for which cooler will provide sufficient cooling on its own but I didnt get any straight forward answers. Eventually I gave up and decided to go with the biggest rad I could fit(hayden 679) with a bypass thermostat(derale 13011) to prevent over-cooling.

 

[redstar]

I decided on a 3/4" cooler instead of a 1-1/2" cooler. I did some sketchy math to come to that decision haha.

I found that all the 3/4" coolers had a similar ratio between the area of the cooler(height * length) and the cooling capacity of the cooler. Then I found that all the 1-1/2" coolers also had a similar ratio. Using the average of each of the ratios, I went looking for a cooler with the highest cooling capacity that would still fit.