Transmission Oil Cooler

[miketedeschi]

Hey guys,

I am going to be adding an aftermarket transmission cooler this weekend to my 2006 Denali with 45,000 miles on it. I tow a 27 foot boat around locally but I will be making a 4 hour trip towing the boat next month. I dont like the transmision temp gauge when it's around 200, i like it at 150. Am i being too cautious?

I'm assuming i should flush the transmission while i'm at it? but now that i think about it i actually have no idea what that means. does flushing a transmission mean you flush some type of cleaning solution through it or am i just doing an oil change where i simply drain, change a filter, and put new fluid in?

Is 45k an OK time to change the fluid in my tranny if it's never been changed?
Are there synthetics?

any advice would be cool. I will take lots of pics of the install and do a write up, and also do some before and after testing towing the boat to see how much it helps. I know JK already did one, but more pics can't hurt!

Thanks guys.

 

[Sepiroth]

Yes have your transmission fluid flushed. What they will do is flush your old tranny fluid out using new fluid which is put in from one of the tranny cooling lines. Once they are done with that, have them drop the pan, clean it out, install a new trans filter, and refill the trans pan.

This might end up costing you a lil over $100.00. Having it done this way will get you a 99% tranny flush.

 

[withac]

A tranny flush at that low mileage shouldn't cause any problems but some people might think it was a waste, how soon does the manual say to change the fluid? You can do a pan drop and top it off with synth. I talked to a Royal Purple rep, for an older transmission he recommended against a flush and suggested the pan drop and filter change using RP. Said the RP film strength was so much stronger than the factory fluid that it would improve/over power the stock fluid. He recommended another pan drop after another 5K miles to get a higher concentration of RP in the tranny. the flush you need to pay to have done, you can do the pan drop yourself, it's pretty easy but can be messy.

 

[JennaBear]

I just installed a B&M cooler on my Tahoe. Definitely doesnt hurt!

 

[Sepiroth]

LOL, I find it kinda funny that the RP rep stated to change the fluid again in 5K. Hell might as well do a flush then since after 5K you would have replaced what 8-9 quarts of fluid. A typical AT hold 12-13 quarts of fluid.

 

[withac]

LOL, I find it kinda funny that the RP rep stated to change the fluid again in 5K. Hell might as well do a flush then since after 5K you would have replaced what 8-9 quarts of fluid. A typical AT hold 12-13 quarts of fluid.

That was exactly the point, that way you have a higher concentration of the RP without the potential problems of flushing a high mileage tranny.

 

[Chasmanian]

Flushing an old tranny can send lil shaving to places they don't need to go. Better to drop the pan and clean first. I think RP is on the right track. I have heard lots of storie about people getting a trans flush and a few thousand mile later the trans has problems.

 

[Gordo]

I just did mine today But I get the hook up, took it down to my uncles job and he did it for $50 with the bg transmission cleaner and conditioner too. We just hooked it up with one of the cooling lines on the radiator.after we poured the cleaner in and let the machine do its work. It probably took about 10 minutes before the oil came out clean. but I would recommend the flush at about 40k especially if your doing alot of towing, Im just like that aswell like the keep the tranny cool.

 

[JKmotorsports]

You can never be too cautious with trans fluid. The cooler you can keep it, the better, especially if you're towing. B&M makes one with an aux fan pre-mounted on the cooler.
If your vehicle has a lot of miles (roughly 80K or more) and the trans has NOT been regularly maintained (usually about every 30K-35K miles), I wouldn't recommend replacing the fluid and filter. The old fluid that has been in the trans is now gritty from small particles worn from the internals. This gritty fluid is actually providing needed friction for the worn internal parts of the transmission (i.e. bands/clutches). Changing the fluid and replacing the filter will remove this friction that the internal transmission parts have become dependent upon. If you have not been regularly maintaining the transmission, you might actually be doing more harm than good if you replace the fluid in a high mileage trans. Now, if the fluid has been regularly serviced and you're not having any trans problems, then you should keep servicing the fluid and filter at regular intervals. I usually service mine around 30-35K miles.

 

[73shark]

Remember when you just drop the pan and refill, you are only replacing the fluid that's in the pan. There's still old fluid in the torque convertor, valve body, cooler, etc.

 

[EliteTahoe]

do as jennabear. Get yourself a transcooler.
My own hoe got one, never bad to have the trans cooled, when towing heavy loads.

Bad thing is.....
Discovered some red fluid at my drivein. After a while, I saw that the tensioner for AC jumped off and laying on the pipes. Almost lost 2 litre of trans fluid and trans started to misshift while revving.
Fixed the pipes, refilled trans, never got problems since.

Get the pipes properly installed, and protect the pipes.
Theres no LOW level warning on trans.

 

[02HOLS]

You can never be too cautious with trans fluid. The cooler you can keep it, the better, especially if you're towing. B&M makes one with an aux fan pre-mounted on the cooler.
If your vehicle has a lot of miles (roughly 80K or more) and the trans has NOT been regularly maintained (usually about every 30K-35K miles), I wouldn't recommend replacing the fluid and filter. The old fluid that has been in the trans is now gritty from small particles worn from the internals. This gritty fluid is actually providing needed friction for the worn internal parts of the transmission (i.e. bands/clutches). Changing the fluid and replacing the filter will remove this friction that the internal transmission parts have become dependent upon. If you have not been regularly maintaining the transmission, you might actually be doing more harm than good if you replace the fluid in a high mileage trans. Now, if the fluid has been regularly serviced and you're not having any trans problems, then you should keep servicing the fluid and filter at regular intervals. I usually service mine around 30-35K miles.

Glad i read this! I bought my Tahoe @ roughly 85k miles from a dealership. Tranny, including fluid, was services, but I have not service the tranny since. AND I drive a little over 50 miles a day! As of now, I almost at 117k miles. So as for my situation, would you say purchasing a tranny cooler would be more in my best interest rather than flushing out the old fluid???

thanks!

 

[EliteTahoe]

Since you're going to take a ATF change, it would not take any much more to install a cooler.

But if you have to choose, I would go for atf change.

 

[withac]

Do a search for posts with my username. I’m not an expert, far from it, but somewhere in here I’ve posted some feedback I got from people who are, namely a Royal Purple rep. His explanation of what a flush can do to a high mileage tranny made sense to me. Based on what he told me, I’d recommend a pan drop and filter change then top off with a real high quality fluid like the RP. Coolers always help. If your ‘Ho came with the tow package it already has an auxiliary cooler but it’s small. I replaced my stock aux. cooler with a larger one right after I had the tranny rebuilt.

 

[Dahlar]

Is there a direct swap higher capacity/efficiency tranny cooler?

 

[withac]

Is there a direct swap higher capacity/efficiency tranny cooler?

Because of the way these things, at least mine (2000, 5.3) are mounted I would doubt it. I had wanted to leave the stock and plumb the extra aux. in too but the fittings were so tight I cracked the stock aux cooler taking it off. It turned out to be a moot point. The stock aux cooler is mounted with rigid plumbing so it would have been next to impossible to take off from the stock fittings, route to the second aux, then back into the stock. There just wouldn't be any room without some major re-plumbing. My cooler is just larger and it's basically like a small radiator. I've seen some after market coolers that even have their own cooling fans. I'm no expert but I'd think that would be for a tranny that was getting some serious abuse. Normal use and occasional towing would prolly be okay with something moderately larger than the stock. I'm sure if I'm wrong someone will tell you. This is where I had planned to look to buy one but then a member on another forum made me a good deal one one.

http://motors.shop.ebay.com/merchant/oregonperformancetransmission

 

[41racing]

I'm a mechanic, I work on gm trucks and suv's almost every day. Install the cooler and have your trans flushed. You don't need to "service" your trans every 30k, unless you get the fluid hot. But then the mileage has nothing to do with it. You could flush it, go out and get the fluid too hot in just a matter of miles and need it flushed again. The fluid getting "gritty" and becoming required is not the case at all, again have your trans flushed. Most of the trans that get flushed on higher mileage trucks and then develop problems soon after, are problems that were there before the flush. Also another common thing that most people don't realize is, most of the time when a trans goes bad it isn't clutches or bands it's some other "hard" part. Often times trans. shops will reuse the clutches and bands, as they are still good. Also don't tow in overdrive, it's not recommended by gm or any tranny guy. It creates a ton of heat, which kills your trans. Also if your truck is 4wd always use low range when pulling your boat out of the water. If you don't you risk seriously overheating the fluid. I've seen it many times. A guy is pulling out the boat and it's on an incline, he has to give it 3/4 throttle to get it moving. All that is doing is creating a ton of heat in the torque converter, use low range, that's what it's there for.

 

[0352Marine]

I'm a mechanic, I work on gm trucks and suv's almost every day. Install the cooler and have your trans flushed. You don't need to "service" your trans every 30k, unless you get the fluid hot. But then the mileage has nothing to do with it. You could flush it, go out and get the fluid too hot in just a matter of miles and need it flushed again. The fluid getting "gritty" and becoming required is not the case at all, again have your trans flushed. Most of the trans that get flushed on higher mileage trucks and then develop problems soon after, are problems that were there before the flush. Also another common thing that most people don't realize is, most of the time when a trans goes bad it isn't clutches or bands it's some other "hard" part. Often times trans. shops will reuse the clutches and bands, as they are still good. Also don't tow in overdrive, it's not recommended by gm or any tranny guy. It creates a ton of heat, which kills your trans. Also if your truck is 4wd always use low range when pulling your boat out of the water. If you don't you risk seriously overheating the fluid. I've seen it many times. A guy is pulling out the boat and it's on an incline, he has to give it 3/4 throttle to get it moving. All that is doing is creating a ton of heat in the torque converter, use low range, that's what it's there for.

I too have worked on these vehicles and trannys for years and couldn't agree more very well put.:thumbsup: Usually what overheats first "hard" part is the pump.