Transmissio Cooler Installation - Arrrrrrrgh!

nfisherman · March 22, 2008

After careful consideration, I decided to add a transmission cooler to my '08 Yukon XL. A checked with my dealer and a couple of independent mechanics. The installed price was around $300. I saw that I could get the GM cooler kit from GM PartsDirect for about $90. I decided to do it myself and spend my savings on my boat. I picked the GM kit, hoping that it might be better than aftermarket if I ever have a warranty problem with my transmission. Both of my trailers are light, so I don't need anything heavy duty anyway.

The installation is done and everything works great. I haven't had much time to drive it yet, but I can already tell that the tranny warms up more slowly than it used to. This is one project I wouldn't do again. I couldn't figure out how to remove the grill, so I just removed the bolts and rivets at the top and flexed the plastic enough to slip everything in there. It worked, but the process wasn't pretty. A garage would have put the car on a lift where the bottom of of the car would have been accessible. I did it in my driveway with the car on ramps. I was forced to bend my neck and arms into unspeakable postions to snake the new rigid transmission cooler line over the frame, around the engine and past the exhaust pipes; all while lying on cold concrete. Suprisingly for one of my projects, there was no loss of blood, but I have a few aches that I didn't have yesterday. I'll cough up the extra $200 on my next truck.

varsis · March 22, 2008

After careful consideration, I decided to add a transmission cooler to my '08 Yukon XL. A checked with my dealer and a couple of independent mechanics. The installed price was around $300. I saw that I could get the GM cooler kit from GM PartsDirect for about $90. I decided to do it myself and spend my savings on my boat. I picked the GM kit, hoping that it might be better than aftermarket if I ever have a warranty problem with my transmission. Both of my trailers are light, so I don't need anything heavy duty anyway.

The installation is done and everything works great. I haven't had much time to drive it yet, but I can already tell that the tranny warms up more slowly than it used to. This is one project I wouldn't do again. I couldn't figure out how to remove the grill, so I just removed the bolts and rivets at the top and flexed the plastic enough to slip everything in there. It worked, but the process wasn't pretty. A garage would have put the car on a lift where the bottom of of the car would have been accessible. I did it in my driveway with the car on ramps. I was forced to bend my neck and arms into unspeakable postions to snake the new rigid transmission cooler line over the frame, around the engine and past the exhaust pipes; all while lying on cold concrete. Suprisingly for one of my projects, there was no loss of blood, but I have a few aches that I didn't have yesterday. I'll cough up the extra $200 on my next truck.

I have one of these on my current truck. I don't notice it heating up slower, mine was always slow. Than again it's a v6 dakota. I am looking into buying a gmc soon. But my local mechanic did it for 80 bucks while installing the tranny on the truck. He also removed a one way valve which can cause some problems. But it is good thing to have, Tranny stays cooler and extends the life of it. And if something were to happen in your radiator like a rock go through it. there is nothing to worry about because it's separate rather than two streams in one cooler. I also noticed the rest of my truck staying cooler as the rad only had to cool the engine not the engine and tranny. Just my 2cents, I think they are worth it even if you like to be hard on the gas... lol.

WFO · March 22, 2008

On my truck the dealer charged me $150.00 to install. It was money well spent. I was planning on ding it myself. When I got it I looked it over and said "No way I'll end up breaking something". So I let the dealer do it. From what you are saying I'm glad I did.

topdollr · March 23, 2008

With the new cooler do you replace the stock lines with the new ones that come with the kit?

I am looking at adding one to my truck and want to know what's involved.

Did you happen to take any pics of the installation?

thanks

solarjustin · March 23, 2008

I did the same thing this past summer on my 04(new to me lastyear). I orderd the cooler online because it was way cheaper than any dealer around here, and I though it would be an easy job. 4 hours later in the driveway I was done. The hard lines are a pain in the @$$ to get in, and the instructions don't give you any tips either. I think this job would of been easy if I had drove 2 hours to my buiddes house because he has a lift in his grage.

If I had to do it again, I would either pay the dealer or at least have my truck on a lift.

NorCal57 · March 23, 2008

I was forced to bend my neck and arms into unspeakable postions to snake the new rigid transmission cooler line over the frame, around the engine and past the exhaust pipes; all while lying on cold concrete. Suprisingly for one of my projects, there was no loss of blood, but I have a few aches that I didn't have yesterday. I'll cough up the extra $200 on my next truck.

sounds like you eliminated the radiator hook up to the tranny? Way back when I was a mechanic, I was taught to install the add-on transmission cooler in the return line from radiator to tranny. Doing it that way, the tranny is getting a lot cooler fluid running through it. I also found it easier to install also.

Adding the 2nd cooler is on m y list of things to do before summer gets here and time to pull the boat. We take a couple of trips a year pulling in 100º+ outside temps....2 yrs ago it was 116º and the A/C in the truck went out. Needless to say, for 3 hrs up my wife was not a happy camper.

varsis · March 23, 2008

I was forced to bend my neck and arms into unspeakable postions to snake the new rigid transmission cooler line over the frame, around the engine and past the exhaust pipes; all while lying on cold concrete. Suprisingly for one of my projects, there was no loss of blood, but I have a few aches that I didn't have yesterday. I'll cough up the extra $200 on my next truck.

sounds like you eliminated the radiator hook up to the tranny? Way back when I was a mechanic, I was taught to install the add-on transmission cooler in the return line from radiator to tranny. Doing it that way, the tranny is getting a lot cooler fluid running through it. I also found it easier to install also.

Adding the 2nd cooler is on m y list of things to do before summer gets here and time to pull the boat. We take a couple of trips a year pulling in 100º+ outside temps....2 yrs ago it was 116º and the A/C in the truck went out. Needless to say, for 3 hrs up my wife was not a happy camper.

Yes that is good way, but defeats the purpose of a LPD cooler. It is to prevent mostly contamination... That is why you do it separate.

diehrd · March 23, 2008

Back when I was in the tranny Business we never used a cooler in line with a radiator , And the tranny runs cooler by not running it into the rad . To this day i still wonder why on earth people think sending the oil through 2oo plus degree water is such a great idea ?

And as far as it warming up slower thats not an issue at all ,, matter of fact you are better off with cooler fluid then hot fluid

C & A s Dad · March 23, 2008

If you decide to elimite the internal cooler, you have to have a much larger external cooler. Every trans cooler company and OE mfg out there always runs the fluid through the internal radiator cooler first. You ask why you woud run oil through 200+ degrees first, it is because the oil is much hotter than this in most cases and the 200 degree radiator cools it down before entering the external cooler. Also, in extremely cold climates, without the fluid running through a radiator, you run the risk of overcooling the fluid.

Check B & M, Hayden, DeRale or any other mfg and look at any OE set up you want and they always run through the radiator first. The only time you would not do this is on a race car set up.

As far as the OE cooler installation from the original post, I am sure this set up looks good and I can understand you wanting to do this in case a warranty issue came up. However, I removed my OE cooler and replaced it with a larger set up becasue I needed extra cooling for my climate and for towing my 6500 lb camper. If done right, there are no risks and they can look as good or better than the OE set up. Glad you added one, you will be happy you did. IMO, every truck should have a external cooler from the factory.

diehrd · March 23, 2008

If you decide to elimite the internal cooler, you have to have a much larger external cooler. Every trans cooler company and OE mfg out there always runs the fluid through the internal radiator cooler first. You ask why you woud run oil through 200+ degrees first, it is because the oil is much hotter than this in most cases and the 200 degree radiator cools it down before entering the external cooler. Also, in extremely cold climates, without the fluid running through a radiator, you run the risk of overcooling the fluid.

Check B & M, Hayden, DeRale or any other mfg and look at any OE set up you want and they always run through the radiator first. The only time you would not do this is on a race car set up.

As far as the OE cooler installation from the original post, I am sure this set up looks good and I can understand you wanting to do this in case a warranty issue came up. However, I removed my OE cooler and replaced it with a larger set up becasue I needed extra cooling for my climate and for towing my 6500 lb camper. If done right, there are no risks and they can look as good or better than the OE set up. Glad you added one, you will be happy you did. IMO, every truck should have a external cooler from the factory.

Get a good sized cooler and run it independent of the radiator , how do I know this works ,, Any one remember the Small s-10 blazers when they came out ? Boxy small grill area small radiator ? 700R-4 Tranny. Any one picture those mini Blazers ?

There biggest problem was pulling a trailer , when under load up a hill the tranny breather tube would push fluid out and cause the tranny to fail.The fluid actually BOILED OUT of the units.

The fix , remove tranny from radiator cooling system and install a good sized air cooler on front of radiator. We did this at least 100 times ,, not only does this make the unit run cooler it increases the life of the unit as well.

So if the directions are your source of information remember this , there compelled to follow the OEM set up for warranty requirements, that does not mean there suggestion is the best way to do it , all it means is it is slightly better doing it that way then leaving the rad to do all the cooling and it ensures the manufacture warranty will not be affected.

So please , do not quote something you read when you have a guy who ran several tranny shops and did this to thousands of cars and trucks and several cases did this on lift line buses ( ya buses, Allison transmissions ) , and tow truck service company trucks ..

It is akin to us modifying a valve body to allow T/Q oil to drain back faster prior to GM issuing a Bulletin and upgrade plate to solve the issue we where finding , we must have been dumb for making our own fix to an issue no one had written directions for

nfisherman · March 23, 2008

I was forced to bend my neck and arms into unspeakable postions to snake the new rigid transmission cooler line over the frame, around the engine and past the exhaust pipes; all while lying on cold concrete. Suprisingly for one of my projects, there was no loss of blood, but I have a few aches that I didn't have yesterday. I'll cough up the extra $200 on my next truck.

sounds like you eliminated the radiator hook up to the tranny? Way back when I was a mechanic, I was taught to install the add-on transmission cooler in the return line from radiator to tranny. Doing it that way, the tranny is getting a lot cooler fluid running through it. I also found it easier to install also.

Adding the 2nd cooler is on m y list of things to do before summer gets here and time to pull the boat. We take a couple of trips a year pulling in 100º+ outside temps....2 yrs ago it was 116º and the A/C in the truck went out. Needless to say, for 3 hrs up my wife was not a happy camper.

No, the kit comes with new lines to hook the cooler in series with the radiator cooler. It adds the cooler on the return line after the radiator.

C & A s Dad · March 23, 2008

Hey Tony, I did not mean to ruffle your feathers. All I am saying it that Trans fluid is typically much hotter than the inside of a radiator and that the hot fluid running through a cooler radiator will help cool it down before it enters the external cooler. There could be some cases where it will work fine if it does not go through the radiator as with the Blazer you mentioned. I will stick to my story that you will need a much larger external cooler to do the job in hot weather if you bypass the radiator. And, if you have one large enough to do the job in hot weather, chances are you will have fluid running well below 100 degrees in climates that see temps at zero or below. We have to remember that trucks run in zub zero weather and 100+.

With that said. I feel the enigneers of every OE I know of are trustworthy for the most part and I have to think they did their homework before running the trans fluid through the readiator before it enters the external cooler. And if the aftermarket companies are following the OE, they must know something as well.

Not saying your system will not work and I understand you have several years of experience. I just do not believe it is the best method of installing an external cooler for the majority of vehicles that need them.

diehrd · March 23, 2008

Not ruffled , why is the engine OIL not passed through the radiator , THINK MAN THINK I know u are smart now think about what I am telling you. I have a ton of Transmission experience , why would I suggest ya go run one on a forum if it was a bad or wrong idea ?

Lets look at what you are saying ,, water heated by thousands of explosions is held back until it reaches 195 degrees, Then released to a single air cooler we call a radiator ..This water is dispersed through tubing connected to thousands of fins which draws the heat off and releases it as air passes through it.

What you are saying is an item that generates way less heat can not be cooled the same way the water is unless we first run it through the air cooler the motor depends on >? That is what you are saying , And have you ever seen the area used in a modern Radiator dedicated to cooling the transmission ? No you have not . If you had seen it and then took a decient air cooler ( Oil Radiator) You would then see visually why MY experience is ahead of your fall back position of directions and auto engineers. Because a tranny cooler of decient size 18 x 12 provides a ton more surface area to cool the oil ,, And provides the Direct affect of air cooling we are seeking with in the radiator to cool it off of its hot water.

The reason a tranny CAN BE COOLED in that hot pool of water to begin with is the heat it needs to shed is small enough to get by with using a built in cooler unlike an engine it will not have runaway temps like a motor has .Most Transmissions will run at 240 degrees or less but not much less , with a decient air cooler you will get it down to 170 or so , which will do 2 things , eliminate overheating engines from affecting a tranny and extend its life because it is running way cooler.

A good quality decient sized air cooler is way more effective from my experience then running it in series.

Starrman · March 23, 2008

but what effect does that have on tranny temps in the winter months when it's 0 degrees out or colder? I know a cool running tranny/fluid is good, but is too cool bad?

Do aftermarket tranny coolers have thermostats to stop the flow to the cooler until the fluid reaches a moderate temp?

dlstewart01 · March 23, 2008

The engineers at General Motors think the same way as you C&As Dad. My factory auxiliary trans cooler that came with the towing package is run through the radiator as well on my 2005 GMC Sierra. Keeps it very cool towing.

I have added trans coolers over the years to many vehicles. I have always used them in conjunction with the radiator trans cooler and never had any issues.

Also I have never seen a manufacture advise otherwise. 100% say run in line with the stock cooler. There must be a reason for this?

Have a good one

Don