3rd gen Transmission Cooler Upgrade

I leave mine pined open all the time and run at 160 degrees probably will pull pin in the winter

 

You changed two variables at the same time. Adding a cooler hasn't made this change for anyone else running WS. I assume the new fluid is the cause of the change

 

I'm interested in this. I removed mine a while ago and sat it by the trash can, expecting to cut it open and take picture later. It was thrown away by the time I went to get it a few days late. Sorry

 

Sure, that's my best guess as well, because I tried bypassing the cooler again for a few days and saw no significant difference. Honestly, it may have been partially due to weather even.

Anyway, since it's summer and I'm up in the mountains more often too, I've just pinned the thermostat for now and the secondary cooler is doing its job perfectly.

 

I need to get around to this. It's been crazy hot and haven't had motivation. I had to rebuild the drivers side CV axle a couple weeks ago and haven't wanted to go back to the garage since lol

 

Hey OP thanks for writing this mod up! My truck was heating up and turning off when I was in 4lo for extended periods. Only thing different I'm doing from OP's install, I am adding automatic inline thermostat switch that will turn the fan on automatically once the ATF hits 180 degrees. I'm just lazy and don't want another switch in the cabin. Plus sometimes I forget the flip these Damn switches .
Here is a link to the inline thermostat I used from Summit.
https://www.summitracing.com/parts/DER-15721

 

This should definitely help. Are you planning on pining the thermostat? I I only ask because the normal temp for this trans is somewhere around 190 degrees! Thats when the OEM thermostat opens up. With that thermostat switch the fan will be on all the time. I live in Phoenix where it's hot as hell and the winter time low is maybe 30 in the early morning so I leave mine pined all the time.

With that said where do you live? I've never had heat issues wheeling in the summer here. I have heard about mud build up between the massive AC condenser and radiator causing over heating issues that are exacerbated when the AC is on.

 

I live in SF Bay area and weather for most part of the year isn't bad at all. I'm not planning on pinning the thermostat because fan will come on at 180 and at that point should cool the ATF down fairly quickly. The problem is at low RPM on the trails because radiator fan is a clutch fan and at low RPM doesn't cool the engine or ATF down fast enough, unless you hit the gas and bring the RPM higher and sometimes when you are on a boulder hitting the gas isn't an option unless you put it in park first. Having the transmission puller fan on at 180 should help the radiator as well since it is a electric fan and will be sending extra air to the radiator as well.
I have clean the condenser could and radiator as well, but truck was still heating up at low speed in 4lo. I blame the whole issue on 35's

 

I hope not lol. I'm planning on 35s soon. I'm going to try the narrower 35 10.5s or 275 80r17s.

I'm still not sure about the thermostat switch. It will literally be on at all times because the normal operating temperature is over 190f. Maybe find one that operates at 200f unless you do want the fan on all the time.

 

I would pin the t-stat and run a manual fan switch so you can turn on a fan while on the trails and turn it off for daily driving. Your temps for dd’ing will be well below 180 if the t-stat is pinned.

I run my t-stat pinned year round and never see more than 150-160*F while running around.

I have see as high as 235 on the trails in the middle of summer while pulling out another truck that had broke, then the truck shut down a bit later for an overheated trans (wasn’t reading temps when it happened). Luckily we were almost off the trail so a 15min break and it fired right back up.

 

Summit does have 190f ones as well like this one, but doesn't come with the fittings. You can always find those fittings at your local hardware store.
https://www.summitracing.com/parts/der-35027/

 

Bought a camper a few months ago, and after towing home last weekend in the TX heat, i wondered if anyone had added a larger trans cooler.
TW did not disappoint.
This is going to be my next mod for sure!

 

So here is the filter cut open after about 25K miles. Nothing really to say about it except it doesn't look too dirty and I didnt see any worrisome metal flakes.

 

Nice. Thanks for the photo. Is there a magnet mounted inside the pan, or was that someone that put one there on there one that I saw in some random thread?

 

I know this is couple yrs old but thinking about something similar after reading all this thread. but...

Has no one gone so far as to bypass the trans lines going into the radiator? Seems if you're going to up the cooling game, why not actually cool the tans fluid instead of cooling the "always going to be 180+ deg trans fluid" that comes out of the radiator. I mean the only reason trans fluid even flows to the rad is because it was an existing heat sink. Sure, faster warm up when idling on snow days, all that non sense. But it just seems stupid for 200+ degree trans fluid to be cooled by 180 deg engine water, then cooled again by an add on trans only cooler.

I bet when bypassing the rad, one could cool it plenty with just a couple small fans on the tow package trans cooler. Put a thermostat on it to only come on if ambient over 70 or something. ?hmmm, I feel a test coming on.

 

FWIW, the inside the rad trans cooler is just a duel wall pipe on cold water side. Trans fluid does not run through any of the fin area. I'd be curious about the stock cooler's btu numbers as well.

 

Your thoughts are sound, and bypassing the radiator can decrease heat load on it from the hotter transmission fluid.
The transmission has a thermostat that doesn’t allow the transmission fluid to be overcooled. Some people, who either tow or run in hot climates pin the thermostat in the open position.
I thought about bypassing the radiator on my Tacoma.
I bypassed the radiator transmission cooler on a V8 engine over 40 years ago and experienced no problems with it in many years of driving and towing in hot and cold weather.

A fan on the stock cooler or a larger aftermarket transmission fluid cooler with or without fan should work just fine.

Some people are worried about voiding their warranty by altering or changing the cooling system.

 

I keep my radiator trans line attached because I don't want to deal with trying to empty it, the mess, and having a dry area corrode or rust. I'm not sure if that's aluminum or steel. My coolant temp has never gone above 201 while towing in the toughest conditions

Side note: my neighbor just bought a new Frontier and the tow package comes with a transmission fluid cooler that is as large as the aftermarket units we are installing in this thread. I thought that was interesting. Do they do it for overkill or does the truck need that much cooling for the trans?

 

What are peoples thoughts on the thermostat sensor? I have a heavy truck on 35s, ultragauge shows me usually over 200 with any sort of wheeling. I don't really want another switch on my dash if I can avoid it, but the highest temp sensor I can find is only 190. Is that going to be too aggressive in terms of cooling?

Sorry to resurrect an old thread!

 

I just pinned my t-stat open this weekend. It will be permanent. Temp was around 140f normal no load highway drive today in 95f ambient.
If anything, at least there's 50 deg cooler air hitting that part of the AC condenser. I plan on adding fan to stock cooler as well for sitting idle/hauling.