Tru-Cool Added to '11 Yukon, coolant or tranny fluid?
 

I have a 2011 Yukon SLE. No towing package so no tranny cooler so I've added the Tru-Cool. I have it mounted and buttoned up, only thing left to do is to tap into the return line to the tranny. I'm piping the cooler in series with the radiator.

From all my research, a lot of guys talk about cooling the tranny fluid, and after installation checking the tranny fluid level. I've only had this vehicle for a year so not intimately familiar with a lot of things, but, for this vehicle, there is no "transmission oil cooler." The "transmission lines," metal lines going from the tranny to the radiator, entering on the bottom, returning from the top of the radaitor, flows coolant from the radiator to the tranny, and cools the tranny fluid that is in the trans. There is no dedicated cooler for the tranny fluid itself. Am I correct?

When I crack that top metal fitting on the radiator, the return line for the transmission, it's just coolant coming out. All of my research was from 07 and back, didn't find a lot on 07+ Yukons.

Just want to make sure I'm getting the max benefiits. I can see cooling the trans fluid directly would be best, but what I'm doing is simply increasing the capacity of the radiator by adding the Tru-Cool and more Dex-cool coolant. Not cooling the trans fluid alone.

Just looking for someone to set me straight.

Coolant is not flowing to your trans if I understand you correct. Trans fluid is flowing into your radiator separatly from the coolant. Trans fluid in the lines will come out and usually need to add a bit when done to make up the added volume the cooler holds. Not much but it needs to be checked after installing and letting the fluids flow

And some people like to bypass the radiator cooler because it has a tendancy to leak and take out your trans. On another note I noticed higher temps when I bypassed mine

When I open up that top metal line going from the radiator back to the trans, that is coolant coming out not trans fluid. Unless they've changed the locations of the lines travelling from the trans to the radiator, the top and bottom metal lines on the radiator, passenger side are for the transmission.

I'm in the NE, from waht I read, the bypass is not necessary. The cooler has an internal bypass.

From all the "research" I've done, the heat transfer between fluids (mostly the coolant/water mixture being the benefit here) is greater than just air.

So bypassing the in-radiator (fluid-to-fluid)cooler, you lose some control over the near-instant spikes of heat that can come from a heavily worked/performance transmission. Adding the cooler after the radiator will help drop the temperature down before it circulates back into the hot transmission, therefore helping protect it further from internal temperature buildup.

Also, anyone who bypasses their in-cooler radiator because they are afraid of internal leaks, needs to think about replacing his/her radiator instead of working around it...no offense :cheers:

I thought it was a little simpler. If you bypass the radiator, meaning run the trans cooling to a dedicated cooler, you're providing more cooling for just the trans. The existing radiator shares cooling for the engine and the trans. Bypassing the radiator makes two dedicated circuits, one for the engine, one ofr the trans. Apparently this can provide more cooling capacity for the trans? Otherwise, adding the additional cooler in series with the radiator just makes a bigger radiator.

Koots, do you know where the oil lines run from the trans to the radiator on my '11. I took a closer look and I think I may have to take off the rodk shield underneath to really get the picture. I can barely see a couple lines on side running in that direction. Would help for me to get underneath too.

Wait, what? You're taking the wrong lines/hoses off if you have coolant coming out. I'm not sure you understand how things are working. The engine's coolant and radiator are totally separate from your transmission. The transmission has one line that comes out of it (carrying transmission fluid) from your trans, through the radiator (through a separate line) then back to the transmission. This is how your trans fluid gets cooled. If you have a trailer package then you would have an external cooler in line with the transmission fluid lines, but it sounds like you do not.

You're right Bruin Boy, but I gotta find out where those lines are on an '11 rig. All of my research shoiwed guys using those two lines I talke about, maybe all thoes guys didn't realize what they were doing either - they were just makign ab igger radiator and nto cooling the trans fluid with the additional cooler. I need to get uner the truck and se where those lines are, I just took it for granted that the trans fluid lines were on the passenger side of the radiator.

Crawl under the truck and trace the lines from the transmission up to the radiator. You don't have very many to chose from, even on an '11.

IMO I would run the cooler and cooler only. No need to run anything through the radiator. It will do just fine cooling it buy it self. It is easier to do it that way any how.