Added transmission cooler (I thought)

[Tyandkate]

I brought my truck in for a oil change and transmission service. While in I decided to have them add a external transmission cooler. So I got the call it was ready. The shop installed a NAPA rapid cool transmission cooler I’ll post a link to it at the bottom of the post here’s my concern.
The cooler was installed in the front of the radiator with a direct path of air. But they bypassed the transmission cooler built in to the radiator. Is this okay or is this going to be a issue while towing? Seeking advice from someone that has more knowledge on the subject. Thanks so much for the advice in advance.

The cooler is 11” wide by 9 1/2” tall 3/4” thick
https://www.napaonline.com/en/p/ATP17510

[Gdetrailer]

I suspect as long as you are not heavy on the gas pedal and the temps are "comfortable" say 80 F or lower and not in a lot of stop and go traffic most likely would be OK.

High outdoor temps along with stop and go traffic plus hard acceleration would be a concern with that small of a cooler by its self.

High temps the cooler can't shed the heat fast enough because it does not have enough square inches of cooling area. Couple that with sitting still are slowly moving in traffic there won't be much cool air moving past the fins.

Just don't drive it like it was stolen..

[Tyandkate]

So question for everyone thanks so much for the advice. I’m going to get this fixed ASAP in the next couple of days I do have some work I’m going to have to use my truck for not pulling the camper but a trailer of 1000 pounds or so. Will this current set up be okay for the time being not driving over 60 miles or so?

[babock]

Tyandkate wrote:
I’d love to know how you added that transmission temp guage it looks factory.

I did the same thing with my Chevy PU. Since the 3/4Ts have that gauge, all you have to do is send the cluster to a speedometer shop and they can add it.

Every cooler's instructions including the Tru-Cool that I added to my truck says to run through the radiator first.

I made my own stainless steel hoses for mine.

[Gdetrailer]

Tyandkate wrote:
I brought my truck in for a oil change and transmission service. While in I decided to have them add a external transmission cooler. So I got the call it was ready. The shop installed a NAPA rapid cool transmission cooler I’ll post a link to it at the bottom of the post here’s my concern.
The cooler was installed in the front of the radiator with a direct path of air. But they bypassed the transmission cooler built in to the radiator. Is this okay or is this going to be a issue while towing? Seeking advice from someone that has more knowledge on the subject. Thanks so much for the advice in advance.

The cooler is 11” wide by 9 1/2” tall 3/4” thick
https://www.napaonline.com/en/p/ATP17510

That little pea shooter?



Way too small to operate without the fluid going through the radiator, it will never remove enough heat all by its' self.

It is just one size larger than Haydens smallest 676 which is for CARS.

To run solo, you would NEED a much bigger cooler, something like Haydens 1260 which is 12"x24" or 1290 which is 18" x 24".

Your radiator cooler has infinitely MORE cooling capacity than your small cooler, therefore to use the small cooler it MUST be connected AFTER the radiator oil cooler.

Per Hayden HERE

"Q. Should the cooler be installed before or after the radiator?

A. Hayden recommends installing the auxillary cooler after the radiator to return the coolest fluid directly to the transmission. Installing the cooler before the radiator will still provide additional cooling and may be necessary in some difficult access applications.

Q. Can you over cool the transmission fluid?

A. Transmissions are not highly sensitive to cool operating tempuratures. However, in sub zero (20-30 F) weather conditions transmission fluid can actually gel up in an external cooler and cease to flow, causing damage. Use of the radiator cooler actually helps warm the fluid under these conditions. It is critical in extreme conditions to use the original equipment cooler in series with the auxiliary cooler and allow vehicle to warm up before driving."

The reason for this is the hot oil goes into the radiator cooler, gets cooled to the coolant temp AT THE BOTTOM of the radiator which IS cooler than the top of the radiator.

Then the oil goes through the small cooler dropping the oil an additional 10-30 degrees or so depending on outside air temps and the speed of air going through the cooler..

Every one of my trucks I have owned which have a FACTORY installed aux transmission cooler has the oil routed through the radiator and THEN to the aux cooler.

[LarryJM]

lawrosa wrote:

Its 8f here in NJ now. If I didnt have the rad cooler the trans would never get warm. In this cold it barely gets over 110f. But if I idle, it warms it up.

The increase in your tranny temp has ABSOLUTELY NOTHING to do with the rad cooler which as I said in my original post WILL NEVER WILL WARM THE TRANNY FLUID regardless of how cold it is outside.

Larry

[JCR-1]

The aftermarket cooler should be last in line (after factory cooler). Although I don't think it makes a major difference in reality.Its going to reduce the temperature either way. After the factory cooler should be the most efficient however make sure there is no metal to metal contact and a suitable air gap in between. Heat is the major concern in auto transmission failures and cold temps are usually not going to be an issue other than maybe producing some condensate water and this will happen either way and usually burns off after it warms up.

[shfd739]

Back when we had a V8 Trailblazer EXT I added a trans cooler and ran it from the radiator out to the new cooler and back to the trans. Kinda defeats having a cooler if the fluid gets cooled then run thru a 200 degree radiator on the way back to the trans.

Cooler worked great and in upper 90 Texas heat the trans never went over 205. Coolant temp pulling hills though would spike to 240ish which I never liked. The 5.3 and 4l60 just didn't like towing a 5800lb trailer.

Replaced it with a Sequoia 6 months after getting the trailer.

[Campfire_Time]

badsix wrote:

last summer with temps near 100deg. I had to go up a 5 mile steep mountain pass with my 2010 GMC 1500 with tow package and a 27' T/T. the towing part was not a problem, I was able to travel 60mph easy. but as I started up the trans temp started up soon we are a little over 200. now the engine is starting to heat up, it was kinda like a nuclear reaction. by the time we hit the top the trans was about 240.

That behavior is perfectly normal. It's a short burst. So long as you are not running long periods at 240 you'll be fine. Are you running Dex VI fluid? If not switch to it. They started using it in 2006 and it's backward compatible for all 4L60E/4L80E transmissions. It's a synthetic blend and runs cooler than the older Dex III.

[SidecarFlip]

DownTheAvenue wrote:
The hot fluid should go to the external after market cooler first, and then to the factory cooler built into the radiator. That way the fluid will be kept at a desirable temperature. The way it is plumbed now, the fluid cold stay way too cold, especially during cold ambient temperatures not towing.

Why would you run thye fluid through the external cooler, cool it down and then run it through the plate heat exchanger in the radiator to heat it back up to engine temperature and then run it to the transmission. Counter productive.

Moat external cooler have built in flow thermostats anyway.

I totally bypassed my radiator plate heat exchanger when I added a pair of Hayden Swirl Cool coolers and plugged the fittings. I did that 12 years ago. My tans temperature is always below 210 degrees and the cooler they run the longer they last. Internal plate coolers on trucks with automatics are basically an afterthought by manufacturers anyway.

That my view and I'm sticking to it. Heat kills slush boxes. Always has.

[Tyandkate]

I’d love to know how you added that transmission temp guage it looks factory.

[Huntindog]

It can be debated whether it should go thru the radiator first, or last. But it should go thru it.

Too cold of tranny fluid temps will not allow the moisture to evaporate from the fluid. The moisture gets in it when conditions are right for condensation to occur. Moisture in the tranny fluid is BAD.

[lawrosa]

LarryJM wrote:
1. Never bypass the in radiator OTO cooler since that is where you get the max heat xfr and no it will never 'WARM' the oil.

2. The radiator OTO cooler will save your xxxx during slow speed or backing up/manuvering like into a camp site when the air flow over the second oil to air (OTA) is basically useless.

3. The proper routing is not a matter of opinion, but based on science and it should go thru the OTO first for #1 reason above and then to the OTA cooler.

Larry

Agreed... Never bypass the rad cooler... I have an 06 silverado, and I added a cooler to the factory one.. Pulling 6000 ft in the NC mountains engine temps when as high as 230f.. Trans never made it past 180f...

Plus when your not moving as was stated the rad cooler is all you got... In the TX heat in traffic youll overheat the trans for sure.. That engine fan dont pull enough air in IMO alone to cool the trans down.

Heres the thing with chevy. The t stat is a 190f. If I idle the truck eventually the trans temp will match the coolant..

Its 8f here in NJ now. If I didnt have the rad cooler the trans would never get warm. In this cold it barely gets over 110f. But if I idle, it warms it up.

With my set up I never go over 180f towing anytime. It only goes to 190f like I said if I sit and idle...

Most times im running 150f 160f like I show below.

These trans have no T stat in them. ( 2006 and below as far as I know. I dont know what the newer chevys do)






Here is 103F outdoor temps towing florida.. A/C on.. Running 70 mph all day...



Heres a vid pulling grade 1st gear 30 mph 3500 rpm. 230f f coolant, and 175f trans. Trans gauge I had added on left dash cluster like a 2500 series..

https://www.flickr.com/photos/93289479@N04/35822079640/in/datetaken/







In summary have the guy put it back through the rad...My opinion

[LarryJM]

1. Never bypass the in radiator OTO cooler since that is where you get the max heat xfr and no it will never 'WARM' the oil.

2. The radiator OTO cooler will save your xxxx during slow speed or backing up/manuvering like into a camp site when the air flow over the second oil to air (OTA) is basically useless.

3. The proper routing is not a matter of opinion, but based on science and it should go thru the OTO first for #1 reason above and then to the OTA cooler.

Larry

[MitchF150]

See... Told ya... 🙂

[badsix]

in cool temps its not going to be a problem ether way. its when your pulling a long mountain pass in the middle of August with the outside temperature around 100 deg. your radiator cooler is already near 200 deg engine temp. then your trans starts to heat up pushing the engine temp up more then external cooler has to take care of both sometimes not being able to handle it. I would think its a good idea to bypass the radiator cooler as they did. that keeps the trans heat out of the radiator and in the axillary cooler.
last summer with temps near 100deg. I had to go up a 5 mile steep mountain pass with my 2010 GMC 1500 with tow package and a 27' T/T. the towing part was not a problem, I was able to travel 60mph easy. but as I started up the trans temp started up soon we are a little over 200. now the engine is starting to heat up, it was kinda like a nuclear reaction. by the time we hit the top the trans was about 240. i'm thinking about getting a larger cooler with a thermostatic fan and not use the radiator cooler.
Jay D.