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Old 01-26-2011, 09:06 PM   #1
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Transmission cooler FYI

I have a 2007 Suburban 1/2 ton, it has 4 wheel drive and the factory towing package. It also has 3:73 gears and the air ride suspension. I assumed it had the factory air to fluid trans cooler. I talked to hoffkm and he said I don't think so. So off with my trusty flashlight, and low and behold I did not have one. hoffkm gave me this link.

GM Parts Direct: Your direct source for Genuine GM Parts

For the factory cooler, I printed it out and went to my local dealer and they did not match the price, but they came close when you figured the shipping.
I had it installed today, it was a balmy day in southwestern Ohio, 24 degrees and after going down the highway for 20 miles, my trans temp was 136 without the cooler, coming back, 3 hours later, we were up to 26 degrees, and the trans temp was 109 with the cooler. My truck has 40,000 miles on it, we changed out the rear end fluid, used Mobil 1 75-90 and I going to do the transfer case, front diff. The transfer case takes a special fluid, it's called Auto-Trak 11, only from GM the part number for this is 12378508. The front diff. does not have synthetic in it, so I'm going to switch both. They are easy, they have both drain and fill plugs. I'm not trying to throw money away, just preventive maintenance.
Hope I have not bored everyone to tears, just some info I thought might be helpful.

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Old 01-26-2011, 10:07 PM   #2
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Hi Randy,

Thank you for posting that information. I am always appreciative of someone adding in some information for towing vehicles. I think we would all be surprised on the number of towing vehicles out there that don't have the proper cooling or fluids on/in them. One thing's for sure, overheating the fluids in an axle or transmission is not something anyone would want to go through while they're on vacation. Not only could it leave someone stranded in the middle of nowhere, but it could wind up costing thousands of dollars to get back on the road again.

I have also jumped on that preventative maintenance wagon and replaced my ft/rr differential and transfer case fluids with an Amsoil synthetic and have zero problems. Eventually, I'm thinking about adding an oil bypass system to my engine so that it can filter out the extra soot produced when I'm towing my Roo up and over some of the passes around here. Another important piece to monitor in a diesel is the exhaust gas temperature (EGT) coming out of the manifold. So an extra gauge to monitor that was a huge plus for me.

Excellent find and I hope that someone else benefits from this information.

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Old 01-27-2011, 12:16 AM   #3
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i have an '07 Avalanche, the same thing as the Burb but with a pickup bed.

i too, have the 5.3 with a 3.73 rear end and factory tow package.
so, the package is supposed to have a tranny cooler. what kind does it have, if it's not the kind you had installed?

i'm also assuming that my Avy may need the same one that yours did.
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Old 01-27-2011, 12:23 AM   #4
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According to what I found out, please don't take this to the bank, just what a mechanic at the dealer ship told me. The factory tow package gives you a larger radiator (maybe an extra core) and the transmission has more coils in the radiator to cool the transmission fluid. Best way to check, get a flashlight and look behind the bow tie in the grill,
If I can help anymore, let me know.
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Old 01-27-2011, 05:06 AM   #5
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The 2007 Avy does not include an auxiliary trasmission cooler as Randy stated. The link he posted is the GM accessory cooler that I installed on my 2007 Avy with good success in keeping the temps down while towing. My father installed an aftermarket cooler on his Silverado and my temps run lower than his when we tow together (and I have about 1500 lbs more camper to lug behind me).

As Randy mentioned, if you have an aux cooler you will see it in front of the radiator.
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Old 01-27-2011, 07:09 PM   #6
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I am going to install a aftermarket transmission cooler on my Avalanche in a couple weeks. My truck came with the tow package, but not the cooler. It's a 2004. I have a buddy that works on cars and we are going to put it in and replace all the fluids.

2004 Chevy Avalanche Z66 W/Transmission Cooler
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