Home » Public Forums » GMCnet » Transmission Radiator - Best Method to Cool Fluids?
| Transmission Radiator - Best Method to Cool Fluids? [message #235458] |
Wed, 08 January 2014 07:35  |
Clark76
Messages: 62
Registered: February 2010
Karma: -2
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STATUS: My transmission is cooled by the OEM Cooler in the radiator + a small auxiliary cooler (~8" x 12") in series in front of the Radiator at the top passenger side.
BACKGROUND: I have a new temperature gauge in the transmission pan that appears to be working correctly, yet, I note that the temperature may be running higher than it should - upwards of 180 degrees on 70 to 80 degree ambient days, extended driving, relatively flat terrain, and towing a Geo Tracker. (Engine Temp will be running around 208) Also Note, the transmission was re-built 2 years ago with a new torque converter and seems to be shifting and running well. My Air Conditioning Cooler with Fan assist is located in front of the Radiator down low on the drivers side.
OPTIONS:
1) Keep everything as is, and become concerned when? or
2) By-Pass the Transmission in he Radiator (plug it off) and install a larger Auxiliary Transmission Cooler in front of the Radiator. (Eliminate the heat transfer between the higher engine radiator temperature and the transmission temperature in the radiator to lower cooling on the transmission)
a) Size of Auxiliary Transmission cooler to use? Dimensions, Fins etc?
b) Hayden http://www.haydenauto.com/Featured%20Products-Transmission%20and%20Engine%20Oil%20Coolers/Content.aspx
or other? With or Without Supplemental Electric Fan?
c) Best Location? Front Lower Passenger side in front of the Radiator?, At an angle in front of the Battery Tray beside the Radiator, Other?
d) Upgrade Transmission Lines, Best Diameter? Steel or high pressure rubber?
I have read numerous posts on this subject with a variety of successful results; however, I have not gleaned which one has been determined to be the most prevalent method to keep the transmission cool. What would that be?
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| Re: Transmission Radiator - Best Method to Cool Fluids? [message #235470 is a reply to message #235458] |
Wed, 08 January 2014 09:23  |
Craig Lechowicz
Messages: 541
Registered: October 2006
Location: Waterford, MI
Karma: 0
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I wouldn't think that 180 is too hot for transmission fluid. Overcooling the trans. (or any oil) is not necessarily helpful, because warm oil flows places you want it better, is easier to pump (less drag) and helps to keep condensation out.
Craig Lechowicz
'77 Kingsley, Waterford, MI
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| Re: [GMCnet] Transmission Radiator - Best Method to Cool Fluids? [message #235472 is a reply to message #235458] |
Wed, 08 January 2014 09:38 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Before getting too upset about that temperature, consider the fact that the
transmission temperature is tied to the engine temperature via the
in-radiator cooler. Eventually, the two should be similar. Then consider
that the Chevrolet Motorhome Chassis Service Guide (which I thought was on
bdub.net but the link no longer works) has a useful table of ATF life vs
Transmission Pan Temperature. Here are some pertinent entries (note that
those are CONTINUOUS temperatures, short excursions either way need to be
averaged in -- how, I don't know):
Temp LIfe (mi)
175*F 100K
195*F 50K
212*F 25K
...
295*F 1,5K
...
390*F 40 MILES
What that says to me is that you'll have to severely over-temp your
transmission to harm the ATF before a normal change is due.
By the way, I encourage everyone to get a copy of that Chevrolet manual
(which I just found here, probably copied from bdub.net
http://hvilket.net/van/P30_Chassis_Svc_Man.pdf). There is a LOT of very
good information in it which is equally as applicable to the GMC as to the
P-30 chassis. Of particular interest is the transmission appendix which
covers oil cooler and filter additions along with the table I mentioned.
JMHO.
Ken H.
On Wed, Jan 8, 2014 at 8:35 AM, Southmayd <wsouthmayd@aol.com> wrote:
>
>
> STATUS: My transmission is cooled by the OEM Cooler in the radiator + a
> small auxiliary cooler (~8" x 12") in series in front of the Radiator at
> the top passenger side.
>
> BACKGROUND: I have a new temperature gauge in the transmission pan that
> appears to be working correctly, yet, I note that the temperature may be
> running higher than it should - upwards of 180 degrees on 70 to 80 degree
> ambient days, extended driving, relatively flat terrain, and towing a Geo
> Tracker. (Engine Temp will be running around 208) Also Note, the
> transmission was re-built 2 years ago with a new torque converter and
> seems to be shifting and running well. My Air Conditioning Cooler with Fan
> assist is located in front of the Radiator down low on the drivers side.
>
> OPTIONS:
> 1) Keep everything as is, and become concerned when? or
> 2) By-Pass the Transmission in he Radiator (plug it off) and install a
> larger Auxiliary Transmission Cooler in front of the Radiator. (Eliminate
> the heat transfer between the higher engine radiator temperature and the
> transmission temperature in the radiator to lower cooling on the
> transmission)
> a) Size of Auxiliary Transmission cooler to use? Dimensions, Fins etc?
> b) Hayden
> http://www.haydenauto.com/Featured%20Products-Transmission%20and%20Engine%20Oil%20Coolers/Content.aspx
> or other? With or Without Supplemental Electric Fan?
> c) Best Location? Front Lower Passenger side in front of the Radiator?,
> At an angle in front of the Battery Tray beside the Radiator, Other?
> d) Upgrade Transmission Lines, Best Diameter? Steel or high pressure
> rubber?
>
> I have read numerous posts on this subject with a variety of successful
> results; however, I have not gleaned which one has been determined to be
> the most prevalent method to keep the transmission cool. What would that be?
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Transmission Radiator - Best Method to Cool Fluids? [message #235481 is a reply to message #235458] |
Wed, 08 January 2014 11:11 |
Jon payne
Messages: 495
Registered: May 2008
Karma: 1
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Senior Member |
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Clark,
I have an AL radiator, external trans cooler from Summit and the Ragusa transmission pan from Applied. With all that, at cruise speed, 85 to 90 degs OAT, the temp in the pan ranges from 125 to the high 130s. In town, going under 30mph the temp creeps up to low 150s. I soon as I pick up speed it will drop back down. I do not tow a vehicle.
So if you are close to 180 while towing I would think that temp range would be expected. Installing an aluminum radiator and a deeper trans pan may help to bring your temps down a bit. The aluminum radiator help a lot to lower and also stabilize engine coolant temp on our coach. Since the AL radiator I have not heard my fan come on as it did before I installed it.
JMHO.
Jon
Jon Payne
76 Palm Beach
Westfield,IN
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| Re: [GMCnet] Transmission Radiator - Best Method to Cool Fluids? [message #235482 is a reply to message #235472] |
Wed, 08 January 2014 11:14 |
Chris Tyler
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
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Senior Member |
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I have experimented with this in the past and found the all around best setup was to keep the in radiator cooler with a large air cooler afterward.
Eliminating the radiator cooling may help a marginal cooling system, but the fluid to fluid heat TF is efficient. The trans temp went up even with a big tranny cooler.
Too large a cooler can also block your radiator cooling, esp if mounted directly. The GMC affords plenty of room to mount it forward and allow air circulation. I also have tried a remote mount with cooling fan and found no gain vs putting it in the airflow.
I have also found the black coolers that look like late model AC evaporators [such as B&M markets] do work better for a given size
Also, if you use the DEI type reflective insulation over the portions near sources of heat, large aluminum lines help as well.
Side note: my 70 El Camino has a tranny cooler that I got from the late Col.
'Chargin Charlie" Beckwith [of Delta Force fame] when he upgraded his to a much larger unit ~27 yrs ago
76 Glenbrook
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| Re: [GMCnet] Transmission Radiator - Best Method to Cool Fluids? [message #235492 is a reply to message #235472] |
Wed, 08 January 2014 12:30 |
bdub
Messages: 1578
Registered: February 2004
Location: Central Texas
Karma: 5
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Senior Member |
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http://www.bdub.net/manuals/P30.zip
On Jan 8, 2014 9:39 AM, "Ken Henderson" <hend4800@bellsouth.net> wrote:
> Before getting too upset about that temperature, consider the fact that the
> transmission temperature is tied to the engine temperature via the
> in-radiator cooler. Eventually, the two should be similar. Then consider
> that the Chevrolet Motorhome Chassis Service Guide (which I thought was on
> bdub.net but the link no longer works) has a useful table of ATF life vs
> Transmission Pan Temperature. Here are some pertinent entries (note that
> those are CONTINUOUS temperatures, short excursions either way need to be
> averaged in -- how, I don't know):
>
> Temp LIfe (mi)
> 175*F 100K
> 195*F 50K
> 212*F 25K
> ...
> 295*F 1,5K
> ...
> 390*F 40 MILES
>
> What that says to me is that you'll have to severely over-temp your
> transmission to harm the ATF before a normal change is due.
>
> By the way, I encourage everyone to get a copy of that Chevrolet manual
> (which I just found here, probably copied from bdub.net
> http://hvilket.net/van/P30_Chassis_Svc_Man.pdf). There is a LOT of very
> good information in it which is equally as applicable to the GMC as to the
> P-30 chassis. Of particular interest is the transmission appendix which
> covers oil cooler and filter additions along with the table I mentioned.
>
> JMHO.
>
> Ken H.
>
>
> On Wed, Jan 8, 2014 at 8:35 AM, Southmayd <wsouthmayd@aol.com> wrote:
>
> >
> >
> > STATUS: My transmission is cooled by the OEM Cooler in the radiator + a
> > small auxiliary cooler (~8" x 12") in series in front of the Radiator at
> > the top passenger side.
> >
> > BACKGROUND: I have a new temperature gauge in the transmission pan that
> > appears to be working correctly, yet, I note that the temperature may be
> > running higher than it should - upwards of 180 degrees on 70 to 80 degree
> > ambient days, extended driving, relatively flat terrain, and towing a Geo
> > Tracker. (Engine Temp will be running around 208) Also Note, the
> > transmission was re-built 2 years ago with a new torque converter and
> > seems to be shifting and running well. My Air Conditioning Cooler with
> Fan
> > assist is located in front of the Radiator down low on the drivers side.
> >
> > OPTIONS:
> > 1) Keep everything as is, and become concerned when? or
> > 2) By-Pass the Transmission in he Radiator (plug it off) and install a
> > larger Auxiliary Transmission Cooler in front of the Radiator. (Eliminate
> > the heat transfer between the higher engine radiator temperature and the
> > transmission temperature in the radiator to lower cooling on the
> > transmission)
> > a) Size of Auxiliary Transmission cooler to use? Dimensions, Fins etc?
> > b) Hayden
> >
> http://www.haydenauto.com/Featured%20Products-Transmission%20and%20Engine%20Oil%20Coolers/Content.aspx
> > or other? With or Without Supplemental Electric Fan?
> > c) Best Location? Front Lower Passenger side in front of the Radiator?,
> > At an angle in front of the Battery Tray beside the Radiator, Other?
> > d) Upgrade Transmission Lines, Best Diameter? Steel or high pressure
> > rubber?
> >
> > I have read numerous posts on this subject with a variety of successful
> > results; however, I have not gleaned which one has been determined to be
> > the most prevalent method to keep the transmission cool. What would that
> be?
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
_______________________________________________
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bdub
'76 Palm Beach/Central Texas
www.bdub.net
www.gmcmhphotos.com
www.gmcmotorhomemarketplace.com
www.gmcmhregistry.com
www.facebook.com/groups/classicgmcmotorhomes
www.facebook.com/groups/gmcmm
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| Re: Transmission Radiator - Best Method to Cool Fluids? [message #235514 is a reply to message #235458] |
Wed, 08 January 2014 15:49 |
Ultravan Owners
Messages: 443
Registered: March 2013
Karma: 0
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Senior Member |
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MTCW on the subject of cooling an Automatic Transmission:
I’m a retired mechanic and I use to have a fleet service business. (This was before I met Marie and moved up here)
I would go on-site to service and/or fix vehicles.
My trucks carried a lot of heavy stuff all the time.
The following is what I did:
I would remove the transmission cooling lines from the hot radiator.
I would run the correct size external transmission cooler with a fan controlled by a temperature switch.
That way the transmission would not run to cold during start up and around town - stop and go traffic.
It would get the moving air when the truck was driven longer and faster.
Also if I ever got stuck in traffic the fan would kick on to cool the ATF down – ONLY when needed.
I never had a transmission problem after that.
BTW - Most of the Corvair Ultravans do NOT not have a transmission cooler and because they are so light - it has not been a problem.
However, I'm restoring a couple Corvair Ultravans and I believe in the set up I have used for years that I purchased what is called FC or Truck powerglides that use external coolers; to put the same set up in all our Corvair Ultravans.
Tony (Ontario Canada)
Marie and I are blessed to have had a 2nd chance to buy our farm.
Still hoping and more importantly praying to be able to build a garage.
Our 1970 Ultravan #520 has an Olds Toronado 455 in back.
[Updated on: Wed, 08 January 2014 15:53] Report message to a moderator |
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| Re: Transmission Radiator - Best Method to Cool Fluids? [message #235811 is a reply to message #235458] |
Sat, 11 January 2014 09:28 |
Ultravan Owners
Messages: 443
Registered: March 2013
Karma: 0
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The following is not precise but you will understand the key point.
Also keep in mind that any overheating will shorten the life of your automatic transmission greatly.
It goes something like this.
An automatic that runs 10% hotter will shorten its life by 20% or more
If it runs 20% hotter than normal it will shorten its life by up to 40% or more
If it runs 30% hotter it could shorten its life by 75% or more.
Again it was long ago when I learned the range and the ones above are simply to show a point.
It is very important to not allow your transmission to overheat or to over fill your automatic transmission.
Good Luck Clark. Please let us know what you find and end up doing.
Sincerely, Tony
Tony (Ontario Canada)
Marie and I are blessed to have had a 2nd chance to buy our farm.
Still hoping and more importantly praying to be able to build a garage.
Our 1970 Ultravan #520 has an Olds Toronado 455 in back.
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| Re: Transmission Radiator - Best Method to Cool Fluids? [message #235824 is a reply to message #235811] |
Sat, 11 January 2014 11:01 |
LarryInSanDiego
Messages: 336
Registered: September 2006
Karma: 0
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I wouldn't eliminate the ATF cooler connection in the radiator. Besides cooling ATF, it's also designed to quickly bring ATF up operating temperature, much like the thermostat does to engine coolant). I would plumb it inline with an thermostatically controlled external cooler.
Larry Engelbrecht
San Diego, CA
'73 26' ex-Glacier
TZE063V100319 03/07/73
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| Re: Transmission Radiator - Best Method to Cool Fluids? [message #235905 is a reply to message #235796] |
Sat, 11 January 2014 23:25 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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| Clark76 wrote on Sat, 11 January 2014 06:41 |
Thanks to all for the replies. For now, I will wait, watch and see if there is any unusual temperature ranges observed under more variety of driving conditions and then re-visit any modifications that could be made. Clark
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I can't believe the replies and the resultant anxiety. Your temperature is totally within normal operating range.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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