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Is this the transmission oil cooler?

N

NC Avalanche

Full Member
Joined
Jan 7, 2007
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10
I have a 2007 Avalanche LTZ 4x4, 5.3, 3.73 rear end.  I don't believe this comes standard with the transmission oil cooler that comes with the 6.0, 4.10.

I spoke to the dealer about installing the GM cooler because I will be towing a 4000 lb travel trailer.  Anyway, when I look through the grill at the radiator, attached to the left side is a small finned 3" by 12" object mounted vertically.  It has a line running into it through the fins and back out.  Both lines run back under the engine towards the transmission.  Is this a small transmission oil cooler?  My trans temp usually runs from 150 to 165 in normal driving.
 
Tough to tell without a pic. You may be looking at the PS cooler. If you have an auxillary Trans Oil cooler, the RPO code on the glovebox sticker will be "KNP". No code...no cooler.

AVid

edit...Just went to look to be sure...the small radiator on the left side (the one you describe) is the cooler for the hydraulic pump that runs the brake booster and power steering.
 
AVid said:
Tough to tell without a pic. You may be looking at the PS cooler. If you have an auxillary Trans Oil cooler, the RPO code on the glovebox sticker will be "KNP". No code...no cooler.

AVid

edit...Just went to look to be sure...the small radiator on the left side (the one you describe) is the cooler for the hydraulic pump that runs the brake booster and power steering.
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Should you have 2 on the outside of your radiator? I've only seen 1 on the outside which almost all the time is the trans cooler.
 
sounds like a Power Steering cooler Like Avid said check your RPO's.? I have an 03 and the PS cooler is the same as what you are describing.
 
SpikeAV said:
Should you have 2 on the outside of your radiator?
Click to expand...

Yes....contrary to popular belief...no 1500 Avalanche had a factory installed aux TOC. The small radiator folks see is on the left side and mounted vertically in front of the engine radiator is the PS fluid cooler. The aux TOC is mounted in front of the engine radiator in the center. The lines from the TOC go to the right side of the truck...while the lines from the PS cooler go down the left.

AVid

edit: I also checked the order specs and there is no option for an aux TOC listed for the Avalanche....including the 6.0l. The 6.0 does have a "KC4" aux engine oil cooler, but no aux TOC.
 
AVid said:
Yes....contrary to popular belief...no 1500 Avalanche had a factory installed aux TOC. The small radiator folks see is on the left side and mounted vertically in front of the engine radiator is the PS fluid cooler. The aux TOC is mounted in front of the engine radiator in the center. The lines from the TOC go to the right side of the truck...while the lines from the PS cooler go down the left.

AVid
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I see.  Thanks.  :wave:
 
Thanks for all of the replies.  Looks like I need to pursue getting a trans oil cooler installed.
 
If you tow, definitely do it. I recommend either the B&M Supercooler or a Long Manufacturing cooler, both in 24k btu size. They are basically the same unit, are pretty cheap, and are an easy install. If you haven't already,  take a look at some of the existing TOC threads.
 
I'll try to keep this short.
A few weeks ago, prior to purchasing our trailer (25 ft, 6000 lb GVWR), I went to the Chevy dealer where I bought my 04 Av.  I asked them to confirm that I have the tranny oil cooler.  The checked my vin # and said that it comes with the heavy duty tow package, that I have.  I then asked the service advisor to show it to me.  We went out and popped the hood and he pointed to the vertically mounted cooler on the driver's side and told me that was it.  After commenting that it seemed rather small for a tranny cooler, I dropped the hood feeling confident that I was in good shape.  This past weekend we went camping about 250 miles from home and on the way home I just got an uneasy feeling that just wouldn't go away.  While unhooking my trailer, my neighbor came over and we got talking about the tranny cooler and since he has always been a chevy truck guy, he took a long look and concluded that I don't have one.  The vertically mounted cooler is indeed for the power steering.  Well, I just came back from the dealer and talked to a different service advisor there and he confirmed that the tranny cooler is not part of the tow package, and my Av doesn't have one.  I now have an appointment to get one installed next Tuesday.  Glad I found out now, rather than towing through the mountains with tranny parts dropping on the hiway......
 
IMHO there is every reason to install an aux trans fluid cooler...especially if you tow

There has been and is still a lot of confusion that exists with owners and dealers (they should know but often don't) regarding OEM installed equipment.

Without discussing the pros/cons of it...the OEM tranny cooler that IS "installed" in our Avs...is merely a tank attached to the bottom portion of the radiator...hardly effective for towing IMHO

So "technically"...the Av comes with a tranny cooler...and this is part of the reason you get so many conflicting answers and why there is so much confusion about listed equipment on the window sticker etc

As many of the excellent responses above indicate...for better trans fluid cooling...install the Aux Tranny Cooler that mounts in front of the radiator...especially if you tow

edit: please note the carefully worded terms I used (tranny cooler vs. aux tranny cooler)
 
AVid said:
Yes....contrary to popular belief...no 1500 Avalanche had a factory installed aux TOC. The small radiator folks see is on the left side and mounted vertically in front of the engine radiator is the PS fluid cooler. The aux TOC is mounted in front of the engine radiator in the center. The lines from the TOC go to the right side of the truck...while the lines from the PS cooler go down the left.

AVid

edit: I also checked the order specs and there is no option for an aux TOC listed for the Avalanche....including the 6.0l. The 6.0 does have a "KC4" aux engine oil cooler, but no aux TOC.
Click to expand...

Avid, I think you're mis-informed (re: the 2007s, anyway)...

In the 2007 Order Guide, there's the following RPO code:
KNP - Cooling, external transmission oil cooler, heavy-duty air-to-oil
1 - Required when (GT5) 4.10 rear axle ratio is ordered.
Not available with (GT4) 3.73 rear axle ratio.

Also:
GT5 - Rear axle, 4.10 ratio
1 - Requires (G80) heavy-duty locking rear differential. Requires (KNP) external transmission oil cooler.
2 - Requires (G80) heavy-duty locking rear differential. Requires (KNP) external transmission oil cooler. Required with (L76) Vortec 6.0L V8 SFI engine.

So, basically, getting the 4.10 rear (which is optional w/ the 5.3, required w/ the 6.0L) will also require you to get the Transmission Oil Cooler (KNP), which will get installed at the factory. Also, though I think this is the same cooler that can be ordered via and installed by the dealer as an accessory (Part# 19171483 for the '07s, #12497071 for the '06 (& previous?)), keep in mind that if it was obtained in this manner it won't be in the list of codes in the glove box.
 
Apparently Part #19171483 is not available for the 2007's yet.  My dealer is unable to get it and I saw a similar situation on a Tahoe forum.  So if you need it now, aftermarket is the only way to go.  I don't know how that affects the warranty, though.
 
lmychajluk said:
Avid, I think you're mis-informed (re: the 2007s, anyway)...
Click to expand...

I stand corrected....This is the first year the 6.0 was available in the AV, so I wrongly assumed it didn't have one. You are indeed right...the 2007 with the 6.0L and the 4.10 rear end gets the KC4 engine oil cooler and the KNP aux TOC.  I suppose the larger trans in the 6.0 would need one.

Thanks for pointing that out.

AVid
 
No problem. Just trying to keep the info here accurate.  :B:

And just to clarify, it's not just the 6.0L that has the TOC - if you get the 4.10 gearing, even w/ the 5.3L, you get the TOC.
 
lmychajluk said:
Avid, I think you're mis-informed (re: the 2007s, anyway)...

In the 2007 Order Guide, there's the following RPO code:
KNP - Cooling, external transmission oil cooler, heavy-duty air-to-oil
1 - Required when (GT5) 4.10 rear axle ratio is ordered.
Not available with (GT4) 3.73 rear axle ratio.

Also:
GT5 - Rear axle, 4.10 ratio
1 - Requires (G80) heavy-duty locking rear differential. Requires (KNP) external transmission oil cooler.
2 - Requires (G80) heavy-duty locking rear differential. Requires (KNP) external transmission oil cooler. Required with (L76) Vortec 6.0L V8 SFI engine.

So, basically, getting the 4.10 rear (which is optional w/ the 5.3, required w/ the 6.0L) will also require you to get the Transmission Oil Cooler (KNP), which will get installed at the factory. Also, though I think this is the same cooler that can be ordered via and installed by the dealer as an accessory (Part# 19171483 for the '07s, #12497071 for the '06 (& previous?)), keep in mind that if it was obtained in this manner it won't be in the list of codes in the glove box.
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I've got a 2010 Z71 with 3.43 ratio and I have the KNP code for the cooler.  I am assuming that I do have the TOC from the factory.  I hope that this is the case as I am about to purchase a 5,000lb travel trailer and don't want the transmission to go.  What is the best way to verify other than the code?  Pretty new to searching for a TOC so I'd need some direction.
 
Look in front of Radiator for TOC
 
My first AV an 02 with a 5.3 had the trans cooler factory installed  :D
 
MC86 said:
I've got a 2010 Z71 with 3.43 ratio and I have the KNP code for the cooler.  I am assuming that I do have the TOC from the factory.  I hope that this is the case as I am about to purchase a 5,000lb travel trailer and don't want the transmission to go.  What is the best way to verify other than the code?  Pretty new to searching for a TOC so I'd need some direction.
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Looks like this pix
 

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The trans oil cooler sits in the middle behind the grille. The power steering cooler is the small one on the drivers side.\

The Pic above is the trans cooler. It was sometimes istalled with the HD towing packages.

Avalon
 
AirJunky said:
I think the cooler lines in my 2005 are on the passenger side, look like they go right into the radiator.
Click to expand...

This is the same arrangement that every vehicle with an automatic transmission has; it IS NOT an auxiliary cooler. The 02-06 Avalanches did not come with an aux trans cooler, period. If you tow anything that even resembles a heavy load you need to install one. The 4L60E is a very weak point just hauling around the weight of the truck.
 
MyBigToy said:
This is the same arrangement that every vehicle with an automatic transmission has; it IS NOT an auxiliary cooler. The 02-06 Avalanches did not come with an aux trans cooler, period. If you tow anything that even resembles a heavy load you need to install one. The 4L60E is a very weak point just hauling around the weight of the truck.
Click to expand...

I get that these lines aren't an auxiliary cooler. But from what I gather, they are the trans cooler for this particular truck. And the cooler lines that one would tap an auxiliary cooler into. I'm looking at the Hayden fin & tube type trans cooler available in Amazon.
 
MyBigToy said:
... The 02-06 Avalanches did not come with an aux trans cooler, period. ...
Click to expand...

My 2004 EXT did.

RPO code: KNP Cooling System Trans, HD

(y)
 
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