Transmission cooler or new rad? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Canadac10 · 10-25-2018, 10:19 AM

Not sure if this is the right section to post, but here goes. In the process of swapping out my 3-speed Saginaw for a 700r4. Going in a '70 C10. Transmission shop is doing the swap for me but I need to address the transmission cooler situation. Truck originally had the I-6 but now has a SB350 out of a 1980 Vette which has a mild cam in it. Original rad, re-cored probably. If anyone has similar experience is it worth it to go with the existing rad and ad a trans cooler or pop for a nice after-market aluminum one that can handle both. At this time I don't have any plans to build the motor beyond where it is. Thanks for any advice!!

72c20customcamper · 10-25-2018, 10:44 AM

The trans cooler in the radiator does more than cool your trans. It also warms the fluid in winter before the friction in the transmission takes over. If your not driving in the cold an external cooler works well

Canadac10 · 10-25-2018, 11:09 AM

Thanks for the reply. Will be driving in the cooler weather so perhaps a new rad is the way to go.

sick472 · 10-25-2018, 11:24 AM

I would bet that the I6 radiator is less effective than a stock v8 radiator (less cores if not smaller dimensions). That, right there, is enough to warrant a new radiator. Unless you plan to put the truck through some heavy trailer pulling or racing, you don't need an external tranny cooler. I personally don't think a cooler can hurt, but it needs to be in conjunction with a radiator, not alone.

Mike C · 10-25-2018, 11:37 AM

Another vote for a new radiator. This would be a good time to upgrade to a 4 core as well. You will need new upper and lower brackets to fit the larger tanks BTW.

**HO455** · 10-25-2018, 12:41 PM

Voting for a new radiator here too! Be sure to check as to what configuration the transmission cooler is. A plate style is best, but some are larger than others. Avoid the cheap radiators that only have a piece of tubing looped inside the tank.

kaycee · 10-25-2018, 09:30 PM

It would be wise to run an xtra trans cooler along with the rad. cooler ,700 do not like heat.

Andy4639 · 10-26-2018, 06:32 AM

My 305 TPI with 700 R4 had 280,000 miles on it when I swapped it for the LS combo. Put the new 3 row aluminum radiator in it and a external cooler and run it through both coolers you will find the transmission will last longer.
GM recommends them to stay under 200*.

Canadac10 · 10-26-2018, 08:38 AM

Thanks for all the reply’s.
Lots of options with aluminum rads. Looking at the Summit house brand, price wise is attractive but what is the consensus? Other brands?
Posted via Mobile Device

Mike C · 10-26-2018, 10:14 AM

How much do you want to spend?

I have a DeWitts I bought for the big block swap into my '64 'vette. With fans it cost almost $1200. It is absolutely awesome.

For my 240Z I bought a Champion and it dropped right in for less than $200. I was quite impressed with the Champion for the money and would buy from them again.

Whatever you get, make sure it is for a 67-72 as the lower hose is turned up and not straight like a 73 and up truck.

cypressbog · 10-26-2018, 01:15 PM

You will be happy with a new 4 core radiator. I see no need for a cooler unless you're towing a lot.

Not sure why a factory 4 core won't work, but if you want to spend money, it's yours to spend.

10-25-2018, 10:19 AM	#1
Canadac10 Registered User Join Date: Oct 2018 Location: Ontario, Canada Posts: 11	Transmission cooler or new rad? Not sure if this is the right section to post, but here goes. In the process of swapping out my 3-speed Saginaw for a 700r4. Going in a '70 C10. Transmission shop is doing the swap for me but I need to address the transmission cooler situation. Truck originally had the I-6 but now has a SB350 out of a 1980 Vette which has a mild cam in it. Original rad, re-cored probably. If anyone has similar experience is it worth it to go with the existing rad and ad a trans cooler or pop for a nice after-market aluminum one that can handle both. At this time I don't have any plans to build the motor beyond where it is. Thanks for any advice!!

10-25-2018, 10:44 AM	#2
72c20customcamper Registered User Join Date: Jul 2018 Location: Catskill Mountains,NY Posts: 8,716	Re: Transmission cooler or new rad? The trans cooler in the radiator does more than cool your trans. It also warms the fluid in winter before the friction in the transmission takes over. If your not driving in the cold an external cooler works well __________________ Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary.

10-25-2018, 11:09 AM	#3
Canadac10 Registered User Join Date: Oct 2018 Location: Ontario, Canada Posts: 11	Re: Transmission cooler or new rad? Thanks for the reply. Will be driving in the cooler weather so perhaps a new rad is the way to go.

10-25-2018, 11:24 AM	#4
sick472 Registered User Join Date: Jul 2015 Location: Sedalia Mo. Posts: 1,131	Re: Transmission cooler or new rad? I would bet that the I6 radiator is less effective than a stock v8 radiator (less cores if not smaller dimensions). That, right there, is enough to warrant a new radiator. Unless you plan to put the truck through some heavy trailer pulling or racing, you don't need an external tranny cooler. I personally don't think a cooler can hurt, but it needs to be in conjunction with a radiator, not alone. __________________ He who is without oil shall throw the first rod. Compressions 8.7:1 1972 C10 1976 C10 (parts truck) 1985 K20

10-25-2018, 11:37 AM	#5
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,727	Re: Transmission cooler or new rad? Another vote for a new radiator. This would be a good time to upgrade to a 4 core as well. You will need new upper and lower brackets to fit the larger tanks BTW. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

10-25-2018, 12:41 PM	#6
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,350	Re: Transmission cooler or new rad? Voting for a new radiator here too! Be sure to check as to what configuration the transmission cooler is. A plate style is best, but some are larger than others. Avoid the cheap radiators that only have a piece of tubing looped inside the tank. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

10-25-2018, 09:30 PM	#7
kaycee Registered User Join Date: Jan 2000 Location: Wyoming USA Posts: 2,446	Re: Transmission cooler or new rad? It would be wise to run an xtra trans cooler along with the rad. cooler ,700 do not like heat. __________________ 2001 Silverado K-1500 2005 FXDWG stage3 69 CHEVY Short/Step 327/4L60 373 posi 63 IMPALA 327

10-26-2018, 06:32 AM	#8
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Transmission cooler or new rad? My 305 TPI with 700 R4 had 280,000 miles on it when I swapped it for the LS combo. Put the new 3 row aluminum radiator in it and a external cooler and run it through both coolers you will find the transmission will last longer. GM recommends them to stay under 200. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB!* After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

10-26-2018, 08:38 AM	#9
Canadac10 Registered User Join Date: Oct 2018 Location: Ontario, Canada Posts: 11	Re: Transmission cooler or new rad? Thanks for all the reply’s. Lots of options with aluminum rads. Looking at the Summit house brand, price wise is attractive but what is the consensus? Other brands? Posted via Mobile Device

10-26-2018, 10:14 AM	#10
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,727	Re: Transmission cooler or new rad? How much do you want to spend? I have a DeWitts I bought for the big block swap into my '64 'vette. With fans it cost almost $1200. It is absolutely awesome. For my 240Z I bought a Champion and it dropped right in for less than $200. I was quite impressed with the Champion for the money and would buy from them again. Whatever you get, make sure it is for a 67-72 as the lower hose is turned up and not straight like a 73 and up truck. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

10-26-2018, 01:15 PM	#11
cypressbog Go Pack Go! Join Date: Nov 2005 Location: Green Bay Posts: 2,669	Re: Transmission cooler or new rad? You will be happy with a new 4 core radiator. I see no need for a cooler unless you're towing a lot. Not sure why a factory 4 core won't work, but if you want to spend money, it's yours to spend.

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