can you bypass you rad trans cooler

[Djsynystr]

I have a second factory trans cooler as well as an add on one thats double the factory ones size in front of my radiator. my trans lines end up going into the radiator before going back to the trans. would it be better to help cool the trans fluid if i wouldn't have it going through the radiator thats already hot from engine coolent and just run it from both coolers back into the trans? has anyone done this with good results? also i ordered a temp gauge and i will be adding that once it arrives. so i am trying to figure out what to do before i add the temp sensor. any thoughts on this would be great. thanks in advance.

 

[Blacksheep Josh]

I have a second factory trans cooler as well as an add on one thats double the factory ones size in front of my radiator. my trans lines end up going into the radiator before going back to the trans. would it be better to help cool the trans fluid if i wouldn't have it going through the radiator thats already hot from engine coolent and just run it from both coolers back into the trans? has anyone done this with good results? also i ordered a temp gauge and i will be adding that once it arrives. so i am trying to figure out what to do before i add the temp sensor. any thoughts on this would be great. thanks in advance.

okay, let me get this straight...

you have a factory external cooler, then another aftermarket cooler thats double the factory external cooler, but the lines from those go into the radiator before going into the transmission?

i know some radiators are designed so they cool the engine and transmission. this is how mine is. yours might be the same, so in effect you'd have 3 coolers going? lol. someone else might want to chime in on this. but if you have at least one cooler hooked up you'll be fine.

 

[Djsynystr]

i tow a small utlitity trailer 3500 lbs or less loaded so i need to make sure. but yes in a sense there are 3 total coolers. one factory add on, one factory in radiator and one i added on that is twice the size of the factory add on.

 

[joecrna]

typically the trans lines go from the trans to the radiator, then to the factory aux cooler then to your add on trans cooler ( or add on to factory aux) then back to the trans. Are you sure yours goes through the radiator last before returning to the trans?

 

[aldive]

Why do you want to do this?

 

[Djsynystr]

im positive it went from trans to factory add on, then into rad. i ran it in series after the factory before the rad. i basically just put mine next to the existing one and went out one into the other. as for why i want to bypass the radiator, isn't the radiator already hot from cooling the engine coolent. lets say the rads at 250+ degrees then why would i want to run already cooler than that fluid into the 250+ degree radiator?

 

[joecrna]

I still think the fluid is likely traveling the opposite direction. That is, it goes into the radiator first, not last. If in fact you are correct about the direction the fluid is moving, than I would suggest you correct this. Your reasoning about the radiator temp is correct.

 

[Djsynystr]

hmm didn't think of it that way. i just looked at placement and not "flow" ok well this still doesn't help my problem. if it goes into a hot radiator before the coolers is it better to bypass the rad cooler with 2 in line?

 

[CDW6212R]

I have had that thought also, and many many times read that the radiator helps. Only once did someone here claim that he was better off without the radiator cooler, after much testing. If I thought it would be cooler for the ATF I would do it, and I believe a lot of others would too. With as many off-roaders as there are here, I tend to think that it helps.

I would suggest that you "T" off the line going to the extra coolers, run them in parallel instead of series. In series the restriction is increased, the other way doesn't do that. I know if costs more and is more complicated to plumb. Good luck,

 

[kert0307]

I think that the reason it runs through the rad is to heat the fluid in colder climates when the engine has recently been started. That way the tranny fluid will reach/maintain its optimal temp range in cold climates.

 

[410Fortune]

im positive it went from trans to factory add on, then into rad.

Not from the factory it didn't

The fluid leaves tranny, enters the top of the fluid/fluid radiator cooler, then leaves and enters the top of the aux cooler.

You can run a stand alone air/fluid cooler yes and bypass the fluid/fluid cooler of the radiator if you want to. You can run 2-3 aftermarket coolers or aux coolers if you wish.

I have spoken to many experts about this exact topic.
Nothing is more efficient then the fluid/fluid cooler built inside your radiator.

The bottom line here is DO YOU HAVE A TEMP GAGE?
Do you know what temp your trans is running at?

There are MANY ways to cool the trans fluid, the main concern is getting it cooled... so however you want to go about it is up to you.

My trans runs at 155 degrees on a hot day, 4x4ing in low range with the AC on high, or 155 degrees pulling a 19' boat through the rocky mountains with the AC on high. I use the factory fluid/fluid cooler in the radiator and then a LARGE (motorhome style) B&M aux cooler... that is all that is required.

Going through 3-4 aux coolers will put strain on the transmission fluid pump, they are designed to push fluid through the radiator and an additional cooler

I vote keep the fluid through the fluid/fluid radiator FIRST, then into your aux air/fluid cooler (huge aftermarket) and then back to the trans, but only after you have some sort of gage to tell you what the tempature is, without the gage all cooling mods are just a shot in the dark.

 

[ExploringNC]

I personally hold not disconnect from the main radiator for several reasons:

1. It warms the tranny fluid up on start up
2. It keeps the tranny fluid warm in winter
3. Tranny goes into warmup mode when cold and if it runs cold all the time then you could damage tranny.
4. and biggest reason how you going to cool the tranny fluid when your in stop and go traffic, you will only get air flowing threw the radiator while moving you will loose cooling from the fan.

 

[Maniak]

I'm one of those people who have run it both ways..

Last summer I was running it from the trans to a 30k gvwr cooler (plate) then into a 24(or 26, can't remember)k gvwr cooler. The 30k cooler has a 10" fan in front of it that runs whenever the trans isn't in lockup (finished installing the current system at the end of summer)

In the winter I put it through the radiator first because it was staying cooler than I like (barely moved off the peg by the time I got to work after a 30+ mile drive to work, mostly freeway)..

Now that its summer again I can tell I'm going through the radiator.. I'm getting 65-70F above ambient on the freeway (in the pan) and 70-80f above ambient in town. Its actually worse now that I'm running a 195F thermostat (was running a 180F before).. Keep in mind.. thats 170F trans temp in the pan on the freeway (its get over 100F here often)

Last summer my trans was seemed to be running cooler (about 10F). I haven't pulled the radiator out of the loop yet but once I do I'll be able to compare apples to apples and see what the trans is running at now..

btw.. I am running synthetic fluid (mobile 1) and have an external filter in the mix too, with a 2700 rpm stall converter (was not chosen on purpose) in a 700r4.

~Mark

 

[CDW6212R]

Mark, I want to hear more of that great information. I need my 99 work truck to run as cool as possible. My 98 truck is a pleasure vehicle and will have twice the stock power. I have extra coolers for each, but still haven't checked temps accurately.

FYI, the five speed automatic(5R55E) does not need any heating from the radiator, ever. It has a circuit in the valve body which bypasses the cooler lines until it warms up. Regards,

 

[cleudard01]

I noticed that on my early 97 sport didn't have the REALLY nice transmission heater right under the tranny....LOL what a place for a catayletic converter!!
Oh, I also have a late 97.

 

[Djsynystr]

ok well my temp gauge arrived today. took a bit of customizing to get the sensor inline but it works great. i took it for a 15 minute ride and let it run for another 20 minutes at idle and temp went to 170ish at highest point sitting still. running it into rad, then add on 1, then add on 2, then back to trans. this was with ac on blast and not towing anything. i am changing the fluid and filter tomorrow as well as installing a welded drain plug in pan. is 170 an acceptable city driving temp?

 

[410Fortune]

170 is a good temp but where in line did you put your gage?
before or aft cooling?

I see you are planning to put it in the pan, 170 is okay for a pan temperature, far below factory

 

[Djsynystr]

no i am adding a drain plug to the pan tomorrw at filter change. i put it on the line coming out of the trans/converter before it goes into the rad cooler. so from what i have read that is the "hottest" fluid you will see. the time it takes to go from converter down 2 feet of tube to the sensor shouldn't lower the temp at all. also ambient temp outside right now is 85 degrees give or take. so im running at about 85 degrees above ambient temp. with old fluid from the previous owner.

 

[410Fortune]

170 is really nice then in that position, however keep in mind the reason they use metal trans lines fromthe factory is they cool the fluid

It would be interesting to see what your tmep is coming back from the coolers! my pan temp is 150-160 hottest normally around 125 on short trips

 

[Djsynystr]

funny you should mention a second guage. i do have space next to my current guage to add another one. i was thinking about doing one next to it for ether pan temp or out of cooler temp. since i already have voltage, oil pressure, coolant temp and outside temp just wasn't sure if that would have been over kill.