Aftermarket Tranny cooler vs. in Radiator cooler - The 1947 - Present Chevrolet & GMC Truck Message Board Network

75stepside · 03-07-2005, 12:50 PM

Just trying to decide what to do... i've got a Turbo 350 w/ a B&M 10.5" converter behind my Fresh 350. When i took the engine/tranny out of the truck originally, it had an aftermarket cooler in front of the radiator. Now, my truck has AC and i'm trying to avoid the sandwich of my AC condensor, radiator and tranny cooler.

Soooooooooooo, is it such a bad idea to just hook the tranny cooling lines up to the radiator, as it is already setup for this... what are the differences between this an an aftermarket cooler?

your opinion???

thanks much!

bigblock73 · 03-07-2005, 01:06 PM

When I purchased my OD trans from Bowtie Overdrives, they told me not to run a auxilary cooler, but rather use the one in the radiator. I never asked why, but they seemed to know what they were talking about...and since their name is all over the transmissions they sell...I have no reason to doubt them.

I would like to hear others opinions as well.

784X4GUY · 03-07-2005, 01:09 PM

Don't really know the differences but my new truck has an auxillary cooler and works really well. It keeps the tranny temps rather low, even in 115 degree phoenix heat...Mike

60-66 Nut · 03-07-2005, 01:16 PM

I've always felt that the radiator cooler was more than sufficient for daily drivers and even mild hot rods. But for heavy towing, I like to use the radiator cooler first to knock the heat down and then go through an auxillary cooler to cool it down even better. Each to his own.

60-66 Nut

truckinbean · 03-07-2005, 07:17 PM

I have mine run through an auxilary cooler and then through the radiator cooler. I used to just have the rad. cooler but my tranny would get up over 220-230 if I drove it for more than 20 miles, especially in town. Of course, this is during the summer with 100+ temps. I put the aux. cooler in and it hasn't gone over 180. The only thing I don't like is in the winter it takes a long time to even get the temp to rise on my guage. I was thinking about putting in a few valves so that I could bypass the aux. cooler in the winter and run it in the summer.

A few things that might be affecting my readings are that my temp sensor is on the output cooler line from the tranny, and it might be soaked with heat off the exhaust pipe in the summer. Also, I had an electric fan that I recently switched out for a fan/fan clutch. I think that maybe since the elec. fan only pulled air through part of the time, the coolant in the rad. stayed hotter and thus didn't cool the tranny fluid as effectively as it would if the air was constantly flowing through the rad.

If that torque converter is a high stall unit, it will most likely generate a lot of heat and it would be a good idea to run the aux. cooler.

Hoods69BadBowTie · 03-07-2005, 07:34 PM

I think if you hook it up to the radiator it should not be a problem at all. The performance auxilary coolers help to keep everything how it should be if you are going to be townig or putting alot of stress on it or even if you have hot weather just keep it cooler.
-Later

86-C10-V6 · 03-07-2005, 07:44 PM

I want everthing I can get to help cool the transmission.
Here in NC, having it get too cold is not really an issue.
I connected mine so that it goes through the radiator cooler first, then through the aux cooler.
My assumption is that the air passing over the aux cooler will be less than 180. If you run through the aux cooler and then through the radiator, the temp of the fluid returning to the transmission will always be 180, or whatever temp your thermostat is trying to maintain. This may be an advantage when you are in extreme cold environment.
If you run through the radiator, the fluid should cool to raidiator temp, then run through the aux cooler for additional cooling.
Just my opinion.

75stepside · 03-07-2005, 11:35 PM

Quote:

Originally Posted by truckinbean

...A few things that might be affecting my readings are that my temp sensor is on the output cooler line from the tranny, and it might be soaked with heat off the exhaust pipe in the summer...

how do you hook up a tranny temp guage? just an engine temp guage fitted onto the steel cooler lines???

86k10 · 03-08-2005, 12:48 AM

[QUOTE=86-C10-V6]
I connected mine so that it goes through the radiator cooler first, then through the aux cooler.

You got it right hooking it up this way, The radiator cooler by itself is not enough even if you are not towing. And I've rebuilt enough in the last 30 years to prove that no problem. As far as the Bow tie people saying don't use an external cooler, why wouldn't they, they know the typical driver doesn't know didly about an auto trans and they would welcome the repeat business. Just a little test for everyone out there, those of you who don't have external coolers, see if your oil is burnt a little or a lot. I'd be interested to know because in all my 30 years of working with them, I have been keeping track and only about 5% came in with mechanical failure, the rest were destroyed by heat and none of them had external coolers. It didn't matter GM Ford Chrysler they all act the same. An auto trans only needs a temp of 100 degrees for continuous operation, they don't have to run as hot as your engine, they can and it's ok, but it's just fine to run cool too. They last much much longer when they do.

twxsby · 03-08-2005, 06:05 PM

I just discovered burnt tranny oil in mine, going to have it rebuilt. I have one external tranny cooler. I will install another one, and maybe a fan. This is the third rebuild for this tranny, I want it to be the last (first since I've owned it, family truck, I know most of the history)

**swervin ervin** · 03-08-2005, 08:16 PM

I agree with 86K10 on the cooler. Bowtie Overdrive may say you don't need an external cooler, but I take it with a grain of salt because I'm not a big fan of BTO anyway. Whoever says the tranny fluid needs to run at engine temps is full of it. Think of it this way. If you only use the radiator cooler, this will cause engine coolant temps to increase, right? Then the higher the temp gets, the higher the fluid temp will get. It's a snowball effect if you ask me.

Jeff,

with a bigblock and 700R4, you better use an external cooler, especially if you have a higher stall converter. Bigblocks run hotter anyway. The tranny fluid will only make it worse, IMO.

bigblock73 · 03-08-2005, 09:46 PM

86K10 and Mike...I understand what you are saying and it makes perfect sense. I think I will run a cooler after the radiator, better safe than sorry I guess.

Glad I read this thread.

**swervin ervin** · 03-08-2005, 11:03 PM

Jeff,

I would run it before the radiator. My take on this is it's better to have the hot fluid reach the aftermarket cooler first. This way you don't have the hot fluid causing the coolant to get hot. Let the add on cooler do most of the work and save your radiator. Of course with two coolers the fluid won't be hot anyway.

Mike

pedrofixlater · 03-09-2005, 06:12 AM

HEAT KILLS TRANNY. number 1 killer of all trannies. if your in a hot enviroment run the cooler after the rad if a cold enviroment reverse that

truckinbean · 03-09-2005, 11:49 AM

Quote:

Originally Posted by 75stepside

how do you hook up a tranny temp guage? just an engine temp guage fitted onto the steel cooler lines???

I used the Autometer temperature manifold #2287. Summit part atm-2287. I have the steel line coming out of the tranny for about a foot, then the temp. man., then braided hose to the coolers. I have the autometer tranny temp gauge # 4357 that comes with the sender.

75stepside · 03-09-2005, 12:22 PM

awesome! that's what i figured... what tranny are you running and which line is the output? where did you run the guage into your cab at?

thanks man!

truckinbean · 03-09-2005, 07:02 PM

I've got a 700r4, and as far I know the lower fitting on the trans is the out and the upper fitting is the return.

For the gauge, I ran the wire through the firewall using the hole where some cruise control related tubes and wires had been before I removed all of it. The gauge is where the stock stereo should be, very similar to swervin's.

apstguy · 03-11-2005, 01:50 AM

BTO told me I had to run an external cooler or they would not warrenty my tranny. It runs through the radiator to the external cooler to the tranny. (I think - it may be the other way around) They told me the bigger the better - I got a big one and with a 2200 stall converter and 100+ heat the tranny can get up to 190. Anyother time of the year (Under 90 degrees) it stay at 160.

03-07-2005, 12:50 PM	#1
75stepside Proud Member Join Date: Nov 2002 Location: Pittsburgh, PA Posts: 741	Aftermarket Tranny cooler vs. in Radiator cooler Just trying to decide what to do... i've got a Turbo 350 w/ a B&M 10.5" converter behind my Fresh 350. When i took the engine/tranny out of the truck originally, it had an aftermarket cooler in front of the radiator. Now, my truck has AC and i'm trying to avoid the sandwich of my AC condensor, radiator and tranny cooler. Soooooooooooo, is it such a bad idea to just hook the tranny cooling lines up to the radiator, as it is already setup for this... what are the differences between this an an aftermarket cooler? your opinion??? thanks much!

03-07-2005, 01:09 PM	#3
784X4GUY Did someone say MUD? Join Date: Aug 2003 Location: Pullman,WA Posts: 1,089	Don't really know the differences but my new truck has an auxillary cooler and works really well. It keeps the tranny temps rather low, even in 115 degree phoenix heat...Mike __________________ Im in the market guys...so keep ya eyes peeled -------------------- Mini trucks are for guys who cant get it up!

03-07-2005, 01:16 PM	#4
60-66 Nut Professional Beer Tester Join Date: Aug 2004 Location: Louisiana Posts: 453	I've always felt that the radiator cooler was more than sufficient for daily drivers and even mild hot rods. But for heavy towing, I like to use the radiator cooler first to knock the heat down and then go through an auxillary cooler to cool it down even better. Each to his own. 60-66 Nut __________________ 60 Ford F100 Custom Cab 61 Apache Short Fleetside 64 C10 Short Stepside 65 C80 409 V8 5spd(X-Firetruck) 83 GMC 350 Olds Diesel 85 GMC Short Bed 86 GMC Short Bed 90 GMC R3500 Crew Cab 92 GMC 1500

03-07-2005, 07:17 PM	#5
truckinbean Registered User Join Date: Jan 2005 Location: Strathmore, CA Posts: 110	I have mine run through an auxilary cooler and then through the radiator cooler. I used to just have the rad. cooler but my tranny would get up over 220-230 if I drove it for more than 20 miles, especially in town. Of course, this is during the summer with 100+ temps. I put the aux. cooler in and it hasn't gone over 180. The only thing I don't like is in the winter it takes a long time to even get the temp to rise on my guage. I was thinking about putting in a few valves so that I could bypass the aux. cooler in the winter and run it in the summer. A few things that might be affecting my readings are that my temp sensor is on the output cooler line from the tranny, and it might be soaked with heat off the exhaust pipe in the summer. Also, I had an electric fan that I recently switched out for a fan/fan clutch. I think that maybe since the elec. fan only pulled air through part of the time, the coolant in the rad. stayed hotter and thus didn't cool the tranny fluid as effectively as it would if the air was constantly flowing through the rad. If that torque converter is a high stall unit, it will most likely generate a lot of heat and it would be a good idea to run the aux. cooler. __________________ '77 Blazer 2wd lowered 5/6 Goodwrench 350/700r4/3.73 Performer intake Performer 1400 carb Sanderson Headers/Dual 2 1/2" Flowmasters

03-07-2005, 07:34 PM	#6
Hoods69BadBowTie Chevys Kick A$$ Join Date: Jan 2005 Location: Zootown, MT Posts: 12,699	I think if you hook it up to the radiator it should not be a problem at all. The performance auxilary coolers help to keep everything how it should be if you are going to be townig or putting alot of stress on it or even if you have hot weather just keep it cooler. -Later __________________ HOODS is what I answer too -'79, '77, '88 Pickup Sold, '85 Camaro, '83 T/A, '81,'83,'90 K5 Blazer All Sold -'79 3/4 ton "Big Yellow Bananna" Lifted 4spd. 39.5 TSL Swampers, The money Pit -'86 K5 Blazer Silverado 6.2 4" lift 35"s -'95 Ext. Cab Shorty 4" Tuff Country rolling 35" M/T's -'83 Monte Carlo T-Tops. 126,500 Original Miles -LATER I would rather push a Chevy then drive a ford!!

03-07-2005, 01:06 PM	#2
bigblock73 yeller Join Date: Oct 2001 Location: Twin Cities Posts: 13,826	When I purchased my OD trans from Bowtie Overdrives, they told me not to run a auxilary cooler, but rather use the one in the radiator. I never asked why, but they seemed to know what they were talking about...and since their name is all over the transmissions they sell...I have no reason to doubt them. I would like to hear others opinions as well. __________________ Jeff 73-87.com 73-87.com Facebook page 73-87 cab corner 6x9 speaker brackets for sale 67-72 cab corner speaker brackets for sale 47-54 cab corner speaker brackets for sale

03-07-2005, 07:44 PM	#7
86-C10-V6 Shadetree Mechanic Join Date: Oct 2002 Location: Youngsville, NC Posts: 100	Heat is the number one killer of transmissions I want everthing I can get to help cool the transmission. Here in NC, having it get too cold is not really an issue. I connected mine so that it goes through the radiator cooler first, then through the aux cooler. My assumption is that the air passing over the aux cooler will be less than 180. If you run through the aux cooler and then through the radiator, the temp of the fluid returning to the transmission will always be 180, or whatever temp your thermostat is trying to maintain. This may be an advantage when you are in extreme cold environment. If you run through the radiator, the fluid should cool to raidiator temp, then run through the aux cooler for additional cooling. Just my opinion. __________________ Dave M. (Hacksaw) 86 C10 Scottsdale LWB, 4.3L, Edelbrock 1904, K&N, 700R4, 3.08 Auburn Performance 89 GMC S-15 Extended Cab 4x4, 4.3L, FI 98 K1500 Xcab, 5.7L, 3.43 Gov-Lok

03-08-2005, 12:48 AM	#9
86k10 Registered User Join Date: Feb 2003 Location: Bertrand, Nebraska Posts: 355	[QUOTE=86-C10-V6] I connected mine so that it goes through the radiator cooler first, then through the aux cooler. You got it right hooking it up this way, The radiator cooler by itself is not enough even if you are not towing. And I've rebuilt enough in the last 30 years to prove that no problem. As far as the Bow tie people saying don't use an external cooler, why wouldn't they, they know the typical driver doesn't know didly about an auto trans and they would welcome the repeat business. Just a little test for everyone out there, those of you who don't have external coolers, see if your oil is burnt a little or a lot. I'd be interested to know because in all my 30 years of working with them, I have been keeping track and only about 5% came in with mechanical failure, the rest were destroyed by heat and none of them had external coolers. It didn't matter GM Ford Chrysler they all act the same. An auto trans only needs a temp of 100 degrees for continuous operation, they don't have to run as hot as your engine, they can and it's ok, but it's just fine to run cool too. They last much much longer when they do. __________________ 98 Neon 97 Grand Prix GT 02 Grand Prix 40th Anniv. 86 GMC 5.0 77 Olds 98 6.6 REAL AMERICANS, DRIVE AMERICAN Last edited by 86k10; 03-12-2005 at 01:32 AM.

03-08-2005, 06:05 PM	#10
twxsby Registered User Join Date: Apr 2003 Location: Cypress, TX Posts: 81	I just discovered burnt tranny oil in mine, going to have it rebuilt. I have one external tranny cooler. I will install another one, and maybe a fan. This is the third rebuild for this tranny, I want it to be the last (first since I've owned it, family truck, I know most of the history) __________________ 84 K-20 Burb 94 Ranger 4X4

03-08-2005, 08:16 PM	#11
swervin ervin You get what you pay for Join Date: Dec 1999 Location: Cherryville, NC Posts: 4,798	I agree with 86K10 on the cooler. Bowtie Overdrive may say you don't need an external cooler, but I take it with a grain of salt because I'm not a big fan of BTO anyway. Whoever says the tranny fluid needs to run at engine temps is full of it. Think of it this way. If you only use the radiator cooler, this will cause engine coolant temps to increase, right? Then the higher the temp gets, the higher the fluid temp will get. It's a snowball effect if you ask me. Jeff, with a bigblock and 700R4, you better use an external cooler, especially if you have a higher stall converter. Bigblocks run hotter anyway. The tranny fluid will only make it worse, IMO. __________________ Mike 1985 Chevy C-10

03-08-2005, 09:46 PM	#12
bigblock73 yeller Join Date: Oct 2001 Location: Twin Cities Posts: 13,826	86K10 and Mike...I understand what you are saying and it makes perfect sense. I think I will run a cooler after the radiator, better safe than sorry I guess. Glad I read this thread. __________________ Jeff 73-87.com 73-87.com Facebook page 73-87 cab corner 6x9 speaker brackets for sale 67-72 cab corner speaker brackets for sale 47-54 cab corner speaker brackets for sale

03-08-2005, 11:03 PM	#13
swervin ervin You get what you pay for Join Date: Dec 1999 Location: Cherryville, NC Posts: 4,798	Jeff, I would run it before the radiator. My take on this is it's better to have the hot fluid reach the aftermarket cooler first. This way you don't have the hot fluid causing the coolant to get hot. Let the add on cooler do most of the work and save your radiator. Of course with two coolers the fluid won't be hot anyway. Mike

03-09-2005, 06:12 AM	#14
pedrofixlater 75 STEPSIDE Join Date: Mar 2005 Location: Suffolk, VA Posts: 92	HEAT KILLS TRANNY. number 1 killer of all trannies. if your in a hot enviroment run the cooler after the rad if a cold enviroment reverse that __________________ Pete 75 Chevy Stepside 70 Buick Skylark/GS

03-09-2005, 12:22 PM	#16
75stepside Proud Member Join Date: Nov 2002 Location: Pittsburgh, PA Posts: 741	awesome! that's what i figured... what tranny are you running and which line is the output? where did you run the guage into your cab at? thanks man!

03-09-2005, 07:02 PM	#17
truckinbean Registered User Join Date: Jan 2005 Location: Strathmore, CA Posts: 110	I've got a 700r4, and as far I know the lower fitting on the trans is the out and the upper fitting is the return. For the gauge, I ran the wire through the firewall using the hole where some cruise control related tubes and wires had been before I removed all of it. The gauge is where the stock stereo should be, very similar to swervin's. __________________ '77 Blazer 2wd lowered 5/6 Goodwrench 350/700r4/3.73 Performer intake Performer 1400 carb Sanderson Headers/Dual 2 1/2" Flowmasters



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03-11-2005, 01:50 AM	#18
apstguy LED King Join Date: Jan 2003 Location: Sacramento, CA Posts: 2,088	BTO told me I had to run an external cooler or they would not warrenty my tranny. It runs through the radiator to the external cooler to the tranny. (I think - it may be the other way around) They told me the bigger the better - I got a big one and with a 2200 stall converter and 100+ heat the tranny can get up to 190. Anyother time of the year (Under 90 degrees) it stay at 160. __________________ Tyler 1985 C10 305 w/ Bowtie OD TH700R4 3.42 LSD 202,000 miles 2006 Ford Focus ZX3 5-speed Stick 2016 Chevy Spark EV Gone: 2002.5 VW GTI 24v VR6 Gone: 2008 VW R32

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