Argh, did I mess my tranny cooler up? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Patrick Sullivan · 07-10-2002, 06:51 AM

When I installed my tranny cooler last night, I decided to run it before the radiator on some advice I had gotten. Now the more that I think about it, the more I think that I messed it up - how can my tranny cooler be doing much if the cooled tranny fluid just goes through the radiator and heats back up?

RipMeyer · 07-10-2002, 07:25 AM

Your correct, however I dont think you messed it up in any way. Just reroute it after the radiator or eliminate the radiator portion alltogeather.

Patrick Sullivan · 07-10-2002, 07:59 AM

Hmm yes, but I already cut one of the lines and I'm out of hose and barb fittings.

Oh well.

*racedvl* · 07-10-2002, 08:09 AM

I did mine rad. first then cooler. Like you said, your gonna just heat it back up once it hits the rad..

Patrick Sullivan · 07-10-2002, 08:31 AM

Yeah..

I've got it switched around now, didn't think the hose I had would stretch far enough.. but it did.

Looks like a definate hack job now, but it'll work I suppose.. just need to wait until the shop opens so I can get some more hose clamps.

mrein3 · 07-10-2002, 09:13 AM

Be careful in the winter. In the winter you want your fluid warmed up some. It may get TOO cold if you go radiator then external cooler.

I have my cooler BEFORE the radiator. I also installed a temp gauge. Not towing my tranny runs a consistant 150 degrees. Towing my boat it runs 185 going down the slab and stays under 200 in stop-and-go traffic. Perfect.

da-burb · 07-10-2002, 09:30 AM

Us northern guys need to run it through the cooler first and the radiator last just to warm the fluid back up to normal operating temps. I have been told running your tranny cold can be just as bad for it as running it hot .

Patrick Sullivan · 07-10-2002, 09:44 AM

Yea, that's what I had heard.

Oh well, it's reversed now.. took it for a drive again, nothing seems to be leaking. The hoses are kinda stretched tight, but hey..

I suppose it never gets under 32 here anyway.. being next to the ocean and all.

Low69CST · 07-10-2002, 09:58 AM

i was going to run mine the radiator then to the cooler infront of the radiator. Anyone use braided line for a tranny cooler?

**ThreeQuarter** · 07-10-2002, 12:15 PM

I thought the first method was the correct one. Tranny fluid is designed to have certain properties at a certain temp, and that temp is set by the radiator. If it's cooler than that, the tranny has to deal with fluid that's too thick, etc. You want it to have a specific temp, not just have it as cold as you can get it. By running it through the radiator last, it will most always be the same temp no matter the weather.

If you run already-cooled tranny fluid into the rad, then you have not only taken the tranny fluid heat load off of the rad, but you'll actually cool the radiator a bit (we're splitting hairs here) by sinking heat back into the tranny fluid.

I believe it's not about how cold you can get it, but instead how close to the correct temp at which it's designed to run.

JJ · 07-10-2002, 12:30 PM

GMCBLU got it right, the object is not to run the transmission at a low temperature. The viscosity of the oil is set for certain parameters, the operating temperature has to be in a given range to allow the lubricating properties, as well as the cooling function. There is a specific reason why the systems are engineered to go through the radiator. You will shorten the life of the tranny if you change it, but then again my dad ran his for almost 180,000 miles before it failed, you'll never convince him that it was incorrect.

68 with 350 TPI · 07-10-2002, 01:17 PM

I dont think you will have to worry about over cooling in except maby in the dead cold of wenter.

Even then you can put a sheild in frnt of it like the big rigs do to keep some heat in if you wanted to.

Heat is the # one killer of the auto trans.

GM has put tranny coolers/power steering coolers on a lot of their work big work trucks without problems for years.

07-10-2002, 06:51 AM	#1
Patrick Sullivan Transcendental Trucker Join Date: Dec 2001 Location: Rockaway Beach, OR Posts: 374	Argh, did I mess my tranny cooler up? When I installed my tranny cooler last night, I decided to run it before the radiator on some advice I had gotten. Now the more that I think about it, the more I think that I messed it up - how can my tranny cooler be doing much if the cooled tranny fluid just goes through the radiator and heats back up? __________________ Patrick Sullivan \| sullivan@oregoncoast.com Rockaway Beach, Oregon 1972 Chevy Cheyenne C-20 1998 Dodge Dakota 4x4 So, fill to me the parting glass And drink a health whate'er befalls... Then gently rise and softly call Goodnight and joy be to you all!

07-10-2002, 07:59 AM	#3
Patrick Sullivan Transcendental Trucker Join Date: Dec 2001 Location: Rockaway Beach, OR Posts: 374	Hmm yes, but I already cut one of the lines and I'm out of hose and barb fittings. Oh well. __________________ Patrick Sullivan \| sullivan@oregoncoast.com Rockaway Beach, Oregon 1972 Chevy Cheyenne C-20 1998 Dodge Dakota 4x4 So, fill to me the parting glass And drink a health whate'er befalls... Then gently rise and softly call Goodnight and joy be to you all!

07-10-2002, 08:31 AM	#5
Patrick Sullivan Transcendental Trucker Join Date: Dec 2001 Location: Rockaway Beach, OR Posts: 374	Yeah.. I've got it switched around now, didn't think the hose I had would stretch far enough.. but it did. Looks like a definate hack job now, but it'll work I suppose.. just need to wait until the shop opens so I can get some more hose clamps. __________________ Patrick Sullivan \| sullivan@oregoncoast.com Rockaway Beach, Oregon 1972 Chevy Cheyenne C-20 1998 Dodge Dakota 4x4 So, fill to me the parting glass And drink a health whate'er befalls... Then gently rise and softly call Goodnight and joy be to you all!

07-10-2002, 09:13 AM	#6
mrein3 Registered User Join Date: Feb 2000 Location: Center City, MN, USA Posts: 3,254	Be careful in the winter. In the winter you want your fluid warmed up some. It may get TOO cold if you go radiator then external cooler. I have my cooler BEFORE the radiator. I also installed a temp gauge. Not towing my tranny runs a consistant 150 degrees. Towing my boat it runs 185 going down the slab and stays under 200 in stop-and-go traffic. Perfect. __________________ '70 cab, '71 chassis, 383, TH350, NP205. '71 Malibu convertible '72 Malibu hard top Center City, MN

07-10-2002, 09:30 AM	#7
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	Us northern guys need to run it through the cooler first and the radiator last just to warm the fluid back up to normal operating temps. I have been told running your tranny cold can be just as bad for it as running it hot . __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087

07-10-2002, 07:25 AM	#2
RipMeyer Registered User Join Date: Oct 2001 Location: Southern New Mexico Posts: 649	Your correct, however I dont think you messed it up in any way. Just reroute it after the radiator or eliminate the radiator portion alltogeather.

07-10-2002, 08:09 AM	#4
racedvl Account Suspended Join Date: Jan 2000 Location: Woodstock, IL Posts: 7,020	I did mine rad. first then cooler. Like you said, your gonna just heat it back up once it hits the rad..

07-10-2002, 09:44 AM	#8
Patrick Sullivan Transcendental Trucker Join Date: Dec 2001 Location: Rockaway Beach, OR Posts: 374	Yea, that's what I had heard. Oh well, it's reversed now.. took it for a drive again, nothing seems to be leaking. The hoses are kinda stretched tight, but hey.. I suppose it never gets under 32 here anyway.. being next to the ocean and all. __________________ Patrick Sullivan \| sullivan@oregoncoast.com Rockaway Beach, Oregon 1972 Chevy Cheyenne C-20 1998 Dodge Dakota 4x4 So, fill to me the parting glass And drink a health whate'er befalls... Then gently rise and softly call Goodnight and joy be to you all!

07-10-2002, 09:58 AM	#9
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	i was going to run mine the radiator then to the cooler infront of the radiator. Anyone use braided line for a tranny cooler? __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks

07-10-2002, 12:15 PM	#10
ThreeQuarter Senior Member Join Date: Jun 2000 Location: Texan in Iowa Posts: 2,522	I thought the first method was the correct one. Tranny fluid is designed to have certain properties at a certain temp, and that temp is set by the radiator. If it's cooler than that, the tranny has to deal with fluid that's too thick, etc. You want it to have a specific temp, not just have it as cold as you can get it. By running it through the radiator last, it will most always be the same temp no matter the weather. If you run already-cooled tranny fluid into the rad, then you have not only taken the tranny fluid heat load off of the rad, but you'll actually cool the radiator a bit (we're splitting hairs here) by sinking heat back into the tranny fluid. I believe it's not about how cold you can get it, but instead how close to the correct temp at which it's designed to run. __________________ Ben '68 Chevy C10 Custom LWB 327/TH400 2nd owner '16 GMC Sierra 1500 SLE Dblcab 4wd 5.3

07-10-2002, 12:30 PM	#11
JJ Lurking Member Join Date: Feb 2000 Location: Forest Grove, OR USA Posts: 196	GMCBLU got it right, the object is not to run the transmission at a low temperature. The viscosity of the oil is set for certain parameters, the operating temperature has to be in a given range to allow the lubricating properties, as well as the cooling function. There is a specific reason why the systems are engineered to go through the radiator. You will shorten the life of the tranny if you change it, but then again my dad ran his for almost 180,000 miles before it failed, you'll never convince him that it was incorrect. __________________ JJ 72 GMC 1500 350 4 Speed, stone stock baby!!!!! 72 GMC K-2500 350TPI 700R4 For those who fought for it, Freedom has a flavor the protected will never know.

07-10-2002, 01:17 PM	#12
68 with 350 TPI Registered User Join Date: May 2002 Location: Wingate NC Posts: 456	I dont think you will have to worry about over cooling in except maby in the dead cold of wenter. Even then you can put a sheild in frnt of it like the big rigs do to keep some heat in if you wanted to. Heat is the # one killer of the auto trans. GM has put tranny coolers/power steering coolers on a lot of their work big work trucks without problems for years. __________________ Life is good with a 6-71 supercharged 355 in a 72 camaro

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