Question on Griffin Radiator

mark sawyer

New member
Aug 20, 2015
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So I installed a Griffin radiator on my coach a few years back, and while i did utilize the built in engine oil cooler, the PO of my coach had gone
with an external trans cooler. According to my trans temp gauge, the external cooler was working fine, so rather than re-plumbing it, I just plugged
the cooler on the Griffin, and left it as is.

This past spring, I towed a car on a trip for the first time, and on some of the bigger hills, I noticed the trans temp creeping up more than I would
like. We have a trip planned for this summer when it will be much hotter, so I am thinking of going ahead and running the trans lines to the cooler
in the radiator first, then on to the external cooler and back to the pan. I own a heavy duty Ford truck as well, and this is the same arrangement
that comes on those from the factory and it works quite well. And while those systems are regulated with a thermostat, I don't really drive my coach
much unloaded or in cold weather, so I'm not really too worried about over-cooling the system.

I also assumed I would pick up quite a bit of cooling capacity by adding in the radiator cooler. Over on one of the Ford Forums, one of the factory
engineers who designed the 5R110 gearbox posts over there, and I remember reading a writeup he did where he mentioned that the radiator trans cooler,
though much smaller, actually cooled quite a bit more than the external air to oil cooler due to the greater efficiency of a water to oil cooler.

However, while I was looking over how I was going to set this up under the coach, I noticed the Griffin is a cross-flow radiator, and that the trans
cooler is seemingly on the hot side only. I don't remember anything about the Griffin being a dual pass or multi-pass radiator, so now I'm kind of
debating whether to go ahead with my plan to run the 2 coolers in series, or update the existing external trans cooler to a larger one and continuing
to bypass the radiator cooler.

Anyone have any thoughts on this or know if the Griffin is a multi-pass radiator or has something else in it's trans cooler design to get the oil over
to the cool side of the radiator?
--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
 
> So I installed a Griffin radiator on my coach a few years back, and while i did utilize the built in engine oil cooler, the PO of my coach had
> gone with an external trans cooler. According to my trans temp gauge, the external cooler was working fine, so rather than re-plumbing it, I just
> plugged the cooler on the Griffin, and left it as is.
>
> This past spring, I towed a car on a trip for the first time, and on some of the bigger hills, I noticed the trans temp creeping up more than I
> would like. We have a trip planned for this summer when it will be much hotter, so I am thinking of going ahead and running the trans lines to the
> cooler in the radiator first, then on to the external cooler and back to the pan. I own a heavy duty Ford truck as well, and this is the same
> arrangement that comes on those from the factory and it works quite well. And while those systems are regulated with a thermostat, I don't really
> drive my coach much unloaded or in cold weather, so I'm not really too worried about over-cooling the system.
>
> I also assumed I would pick up quite a bit of cooling capacity by adding in the radiator cooler. Over on one of the Ford Forums, one of the
> factory engineers who designed the 5R110 gearbox posts over there, and I remember reading a writeup he did where he mentioned that the radiator
> trans cooler, though much smaller, actually cooled quite a bit more than the external air to oil cooler due to the greater efficiency of a water to
> oil cooler.
>
> However, while I was looking over how I was going to set this up under the coach, I noticed the Griffin is a cross-flow radiator, and that the
> trans cooler is seemingly on the hot side only. I don't remember anything about the Griffin being a dual pass or multi-pass radiator, so now I'm
> kind of debating whether to go ahead with my plan to run the 2 coolers in series, or update the existing external trans cooler to a larger one and
> continuing to bypass the radiator cooler.
>
> Anyone have any thoughts on this or know if the Griffin is a multi-pass radiator or has something else in it's trans cooler design to get the oil
> over to the cool side of the radiator?

Mark,

I do not know if the Griffin is a multi-pass or not. As I write this. I am not sure if the OE is multi-pass or not, but I am going to look in my barn
when there next.

Second issue. The transmission cooler part of the OE radiator is in the cold side. I happen to be sure of this because a friend and I were
discussing the cooling system last night and I had it backwards.

Third issue. If you were to run the two coolers in series, your chance of causing trouble is slim. Transmissions are not engines. (Gee) OK, the
reason you do not want an engines lube oil too cold is that you want to be able to drive off the water that is a by-product of combustion. That case
does not exist in a transmission.

Forth issue. If you think about it, you will realize that AFT is not at all like engine oil. It about kerosene. So, no matter how cool it gets, it
will not be far enough out of the viscosity band for that to be an issue.

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Mark,
Out of Curiosity, what was the temp of the the tranny fluid that made you uncomfortable? A lot of the aftermarket fluid coolers won’t even activate
the fan until the fluid gets to be higher than 180*.
Scott
--
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, tankless water heater, everything Lenzi. Alex Ferrera
installed MSD Atomic EFI
Houston, Texas
 
I would run the tranny fluid through the radiator tank cooler then the external cooler . If the tranny failed while it was using the radiator cooler I
would not use this cooler ever again as any debree Left in the cooler could mess up the transmission.
--
Roy Keen
Minden,NV
76 X Glenbrook
 
Mark,

Go to www.bdub.net and download the Chevrolet P-30 Chassis Owners Manual
which he has posted there. One of the appendices covers adding external
oil coolers. It includes a table showing ATF life versus Average
temperature. You'll probably find from the text and chart that you're
overly concerned about your transmission temperature. If not, I wouldn't
hesitate to run through that New Griffin cooler also.

JMHO,

Ken H.

On Fri, May 29, 2020 at 4:27 PM Mark Sawyer via Gmclist <

> So I installed a Griffin radiator on my coach a few years back, and while
> i did utilize the built in engine oil cooler, the PO of my coach had gone
> with an external trans cooler. According to my trans temp gauge, the
> external cooler was working fine, so rather than re-plumbing it, I just
> plugged
> the cooler on the Griffin, and left it as is.
>
> This past spring, I towed a car on a trip for the first time, and on some
> of the bigger hills, I noticed the trans temp creeping up more than I would
> like. We have a trip planned for this summer when it will be much hotter,
> so I am thinking of going ahead and running the trans lines to the cooler
> in the radiator first, then on to the external cooler and back to the
> pan. I own a heavy duty Ford truck as well, and this is the same
> arrangement
> that comes on those from the factory and it works quite well. And while
> those systems are regulated with a thermostat, I don't really drive my coach
> much unloaded or in cold weather, so I'm not really too worried about
> over-cooling the system.
>
> I also assumed I would pick up quite a bit of cooling capacity by adding
> in the radiator cooler. Over on one of the Ford Forums, one of the factory
> engineers who designed the 5R110 gearbox posts over there, and I remember
> reading a writeup he did where he mentioned that the radiator trans cooler,
> though much smaller, actually cooled quite a bit more than the external
> air to oil cooler due to the greater efficiency of a water to oil cooler.
>
> However, while I was looking over how I was going to set this up under the
> coach, I noticed the Griffin is a cross-flow radiator, and that the trans
> cooler is seemingly on the hot side only. I don't remember anything about
> the Griffin being a dual pass or multi-pass radiator, so now I'm kind of
> debating whether to go ahead with my plan to run the 2 coolers in series,
> or update the existing external trans cooler to a larger one and continuing
> to bypass the radiator cooler.
>
> Anyone have any thoughts on this or know if the Griffin is a multi-pass
> radiator or has something else in it's trans cooler design to get the oil
> over
> to the cool side of the radiator?
> --
> Mark S. '73 Painted Desert,
> Manny 1 Ton Front End,
> Howell Injection,
> Leigh Harrison 4bag and Rear Brakes,
> Fort Worth, TX
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
On Sat, May 30, 2020 at 2:56 PM Ken Henderson via Gmclist <

> Mark,
> Roy is very correct when he mentioned that possibly the trans cooler on
> the radiator was not being used as there could have been trans damage that
> caused debris to the cooler.

c

>
> Go to www.bdub.net and download the Chevrolet P-30 Chassis Owners Manual
> which he has posted there. One of the appendices covers adding external
> oil coolers. It includes a table showing ATF life versus Average
> temperature. You'll probably find from the text and chart that you're
> overly concerned about your transmission temperature. If not, I wouldn't
> hesitate to run through that New Griffin cooler also.
>
> JMHO,
>
> Ken H.
>
>
> On Fri, May 29, 2020 at 4:27 PM Mark Sawyer via Gmclist <

>
> > So I installed a Griffin radiator on my coach a few years back, and while
> > i did utilize the built in engine oil cooler, the PO of my coach had gone
> > with an external trans cooler. According to my trans temp gauge, the
> > external cooler was working fine, so rather than re-plumbing it, I just
> > plugged
> > the cooler on the Griffin, and left it as is.
> >
> > This past spring, I towed a car on a trip for the first time, and on some
> > of the bigger hills, I noticed the trans temp creeping up more than I
> would
> > like. We have a trip planned for this summer when it will be much
> hotter,
> > so I am thinking of going ahead and running the trans lines to the cooler
> > in the radiator first, then on to the external cooler and back to the
> > pan. I own a heavy duty Ford truck as well, and this is the same
> > arrangement
> > that comes on those from the factory and it works quite well. And while
> > those systems are regulated with a thermostat, I don't really drive my
> coach
> > much unloaded or in cold weather, so I'm not really too worried about
> > over-cooling the system.
> >
> > I also assumed I would pick up quite a bit of cooling capacity by adding
> > in the radiator cooler. Over on one of the Ford Forums, one of the
> factory
> > engineers who designed the 5R110 gearbox posts over there, and I remember
> > reading a writeup he did where he mentioned that the radiator trans
> cooler,
> > though much smaller, actually cooled quite a bit more than the external
> > air to oil cooler due to the greater efficiency of a water to oil cooler.
> >
> > However, while I was looking over how I was going to set this up under
> the
> > coach, I noticed the Griffin is a cross-flow radiator, and that the trans
> > cooler is seemingly on the hot side only. I don't remember anything
> about
> > the Griffin being a dual pass or multi-pass radiator, so now I'm kind of
> > debating whether to go ahead with my plan to run the 2 coolers in series,
> > or update the existing external trans cooler to a larger one and
> continuing
> > to bypass the radiator cooler.
> >
> > Anyone have any thoughts on this or know if the Griffin is a multi-pass
> > radiator or has something else in it's trans cooler design to get the oil
> > over
> > to the cool side of the radiator?
> > --
> > Mark S. '73 Painted Desert,
> > Manny 1 Ton Front End,
> > Howell Injection,
> > Leigh Harrison 4bag and Rear Brakes,
> > Fort Worth, TX
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
As Jim K recommends go to Appendix 8-1 in section 8. Our transmission temp is typically about 165 Deg. F going down the road towing. I use the radiator cooler plus have a large Hayden flat plane cooler in series. I am with Jim when it comes to keeping the ATF cool. I also do a fluid change every 3 years or so depending on the miles driven. Fluid is cheap and transmission are not. I buy by bulk either 2 or 5 gallon containers and I buy typically at Tractor Supply Co, runs aprox $35 for a 2 gal container of the Traveller Brand. There are many who swear by the high dollar synthetic brands, but as I said I change often and check the pan for disk dust in the bottom. I may not change my filter every time that I change oil. I acquired a number of the AC Delco TF169 filters several years ago so I am still able to go factory on the filters.

JR Wright

>
> On Sat, May 30, 2020 at 2:56 PM Ken Henderson via Gmclist <

>
>> Mark,
>> Roy is very correct when he mentioned that possibly the trans cooler on
>> the radiator was not being used as there could have been trans damage that
>> caused debris to the cooler.
>
> c
>
>>
>> Go to www.bdub.net and download the Chevrolet P-30 Chassis Owners Manual
>> which he has posted there. One of the appendices covers adding external
>> oil coolers. It includes a table showing ATF life versus Average
>> temperature. You'll probably find from the text and chart that you're
>> overly concerned about your transmission temperature. If not, I wouldn't
>> hesitate to run through that New Griffin cooler also.
>>
>> JMHO,
>>
>> Ken H.
>>
>>
>> On Fri, May 29, 2020 at 4:27 PM Mark Sawyer via Gmclist <

>>
>>> So I installed a Griffin radiator on my coach a few years back, and while
>>> i did utilize the built in engine oil cooler, the PO of my coach had gone
>>> with an external trans cooler. According to my trans temp gauge, the
>>> external cooler was working fine, so rather than re-plumbing it, I just
>>> plugged
>>> the cooler on the Griffin, and left it as is.
>>>
>>> This past spring, I towed a car on a trip for the first time, and on some
>>> of the bigger hills, I noticed the trans temp creeping up more than I
>> would
>>> like. We have a trip planned for this summer when it will be much
>> hotter,
>>> so I am thinking of going ahead and running the trans lines to the cooler
>>> in the radiator first, then on to the external cooler and back to the
>>> pan. I own a heavy duty Ford truck as well, and this is the same
>>> arrangement
>>> that comes on those from the factory and it works quite well. And while
>>> those systems are regulated with a thermostat, I don't really drive my
>> coach
>>> much unloaded or in cold weather, so I'm not really too worried about
>>> over-cooling the system.
>>>
>>> I also assumed I would pick up quite a bit of cooling capacity by adding
>>> in the radiator cooler. Over on one of the Ford Forums, one of the
>> factory
>>> engineers who designed the 5R110 gearbox posts over there, and I remember
>>> reading a writeup he did where he mentioned that the radiator trans
>> cooler,
>>> though much smaller, actually cooled quite a bit more than the external
>>> air to oil cooler due to the greater efficiency of a water to oil cooler.
>>>
>>> However, while I was looking over how I was going to set this up under
>> the
>>> coach, I noticed the Griffin is a cross-flow radiator, and that the trans
>>> cooler is seemingly on the hot side only. I don't remember anything
>> about
>>> the Griffin being a dual pass or multi-pass radiator, so now I'm kind of
>>> debating whether to go ahead with my plan to run the 2 coolers in series,
>>> or update the existing external trans cooler to a larger one and
>> continuing
>>> to bypass the radiator cooler.
>>>
>>> Anyone have any thoughts on this or know if the Griffin is a multi-pass
>>> radiator or has something else in it's trans cooler design to get the oil
>>> over
>>> to the cool side of the radiator?
>>> --
>>> Mark S. '73 Painted Desert,
>>> Manny 1 Ton Front End,
>>> Howell Injection,
>>> Leigh Harrison 4bag and Rear Brakes,
>>> Fort Worth, TX
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.gmcrvparts.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org