Home » Public Forums » GMCnet » Re: [GMCnet] GmTrans temp
| Re: [GMCnet] GmTrans temp [message #155421] |
Wed, 04 January 2012 17:16  |
Gary Casey
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Registered: September 2009
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John,
I think that is something like what happens, but as I recall from a chemistry class far back in the last century, chemical reactions typically double in speed every 7 degrees (F or C, I don't remember). Unlike what you read on the net (yeah, it must be true :-), I think at 220F the oil life is more like 500,000 miles. By the time you get to 300F, though, I think the life might be 1,000 miles or less. And I think it is a very nonlinear function, maybe more severe than you are saying. Let's see, 7C is about 10F, so with my prediction, 230 gets you 250,000 miles, 240 is 125,000, 250 is 62,500, 260 is 31,250, 270 is about 16,000, 280 is 8,000, 290 is good for 4,000, 300 is 2,000 and 310 is 1,000. 320 gives a life of 500 miles. Or something like that. And I think I believe it. Our old rule of thumb was that if you saw over 300 you changed the oil at the next reasonable opportunity.
Gary
Found this on the web so it must be right, right?
As a rule of thumb, every 20 degree increase in operating temperature above 175 degrees F. cuts the life of the fluid in half!
At 195 degrees F., for instance, fluid life is reduced to 50,000 miles. At 220 degrees, which is commonly encountered in many transmissions, the fluid is only good for about 25,000 miles. At 240 degrees F., the fluid won't go much over 10,000 miles. Add another 20 degrees, and life expectancy drops to 5,000 miles. Go to 295 or 300 degrees F., and 1,000 to 1,500 miles is about all you'll get before the transmission burns up.
--
John Lebetski
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| Re: [GMCnet] GmTrans temp [message #155426 is a reply to message #155421] |
Wed, 04 January 2012 17:47  |
Gary Worobec
Messages: 867
Registered: May 2005
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Hi,
We have a B+M trans cooler with a thermostatically controlled fan on our
coach in front of the radiator and a mechanical trans temp gauge off the
trans pan inserted into the front of the pan almost centered. We've done
some wicked climbs while towing the Tracker. The hill from Palm Desert to
our house goes from 500 ft to 5000 ft. The Grapevine and the Cajon pass also
come to mind. Our trans temp has never gone above 160 even when the ambient
is 90F and above. The only time I'll see a significant raise in temp (maybe
to 160F) is when we are in stop and go traffic. I guess the starting and
stopping heats the fluid more than a constant pull up an incline.
I'm still using the same fluid that Jim K put in it when we replaced it a
110,000 miles which was 10,000 miles ago. I don;t think it was Synthetic.
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
----- Original Message -----
From: "Gary Casey" <casey.gary@yahoo.com>
To: <gmclist@temp.gmcnet.org>
Sent: Wednesday, January 04, 2012 3:16 PM
Subject: Re: [GMCnet] GmTrans temp
John,
I think that is something like what happens, but as I recall from a
chemistry class far back in the last century, chemical reactions typically
double in speed every 7 degrees (F or C, I don't remember). Unlike what you
read on the net (yeah, it must be true :-), I think at 220F the oil life is
more like 500,000 miles. By the time you get to 300F, though, I think the
life might be 1,000 miles or less. And I think it is a very nonlinear
function, maybe more severe than you are saying. Let's see, 7C is about 10F,
so with my prediction, 230 gets you 250,000 miles, 240 is 125,000, 250 is
62,500, 260 is 31,250, 270 is about 16,000, 280 is 8,000, 290 is good for
4,000, 300 is 2,000 and 310 is 1,000. 320 gives a life of 500 miles. Or
something like that. And I think I believe it. Our old rule of thumb was
that if you saw over 300 you changed the oil at the next reasonable
opportunity.
Gary
Found this on the web so it must be right, right?
As a rule of thumb, every 20 degree increase in operating temperature above
175 degrees F. cuts the life of the fluid in half!
At 195 degrees F., for instance, fluid life is reduced to 50,000 miles. At
220 degrees, which is commonly encountered in many transmissions, the fluid
is only good for about 25,000 miles. At 240 degrees F., the fluid won't go
much over 10,000 miles. Add another 20 degrees, and life expectancy drops to
5,000 miles. Go to 295 or 300 degrees F., and 1,000 to 1,500 miles is about
all you'll get before the transmission burns up.
--
John Lebetski
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| Re: [GMCnet] GmTrans temp [message #155428 is a reply to message #155426] |
Wed, 04 January 2012 17:53 |
Mr ERFisher
Messages: 7117
Registered: August 2005
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the rap on these, was always, that they fail closed
http://www.gmcmotorhome.info/CRANKS.html#COOLER
gene
On Wed, Jan 4, 2012 at 3:47 PM, Gary Worobec <gtw5@earthlink.net> wrote:
> Hi,
> We have a B+M trans cooler with a thermostatically controlled fan on our
> coach in front of the radiator and a mechanical trans temp gauge off the
> trans pan inserted into the front of the pan almost centered. We've done
> some wicked climbs while towing the Tracker. The hill from Palm Desert to
> our house goes from 500 ft to 5000 ft. The Grapevine and the Cajon pass
> also
> come to mind. Our trans temp has never gone above 160 even when the ambient
> is 90F and above. The only time I'll see a significant raise in temp (maybe
> to 160F) is when we are in stop and go traffic. I guess the starting and
> stopping heats the fluid more than a constant pull up an incline.
>
> I'm still using the same fluid that Jim K put in it when we replaced it a
> 110,000 miles which was 10,000 miles ago. I don;t think it was Synthetic.
>
> Thanks
>
> Gary and Joanne Worobec
> 1973 GMC Glacier
> Anza, CA
>
>
> ----- Original Message -----
> From: "Gary Casey" <casey.gary@yahoo.com>
> To: <gmclist@temp.gmcnet.org>
> Sent: Wednesday, January 04, 2012 3:16 PM
> Subject: Re: [GMCnet] GmTrans temp
>
>
> John,
> I think that is something like what happens, but as I recall from a
> chemistry class far back in the last century, chemical reactions typically
> double in speed every 7 degrees (F or C, I don't remember). Unlike what you
> read on the net (yeah, it must be true :-), I think at 220F the oil life is
> more like 500,000 miles. By the time you get to 300F, though, I think the
> life might be 1,000 miles or less. And I think it is a very nonlinear
> function, maybe more severe than you are saying. Let's see, 7C is about
> 10F,
> so with my prediction, 230 gets you 250,000 miles, 240 is 125,000, 250 is
> 62,500, 260 is 31,250, 270 is about 16,000, 280 is 8,000, 290 is good for
> 4,000, 300 is 2,000 and 310 is 1,000. 320 gives a life of 500 miles. Or
> something like that. And I think I believe it. Our old rule of thumb was
> that if you saw over 300 you changed the oil at the next reasonable
> opportunity.
> Gary
>
>
> Found this on the web so it must be right, right?
>
> As a rule of thumb, every 20 degree increase in operating temperature above
> 175 degrees F. cuts the life of the fluid in half!
>
> At 195 degrees F., for instance, fluid life is reduced to 50,000 miles. At
> 220 degrees, which is commonly encountered in many transmissions, the fluid
> is only good for about 25,000 miles. At 240 degrees F., the fluid won't go
> much over 10,000 miles. Add another 20 degrees, and life expectancy drops
> to
> 5,000 miles. Go to 295 or 300 degrees F., and 1,000 to 1,500 miles is about
> all you'll get before the transmission burns up.
>
>
> --
> John Lebetski
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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> _______________________________________________
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--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] GmTrans temp [message #155431 is a reply to message #155421] |
Wed, 04 January 2012 18:33 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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ATF life prediction from the P-30 manual I referenced earlier:
DEGREES F MILES
175 100,000
195 50,000
212 25,000
235 12,000
255 6,000
275 3,000
295 1,500
315 750
335 325
355 160
375 80
390 40
415 Less than 30 Minutes
Temperature as measured in the pan.
Ken H.
On Wed, Jan 4, 2012 at 6:16 PM, Gary Casey wrote:
> John,
> I think that is something like what happens, but as I recall from a
> chemistry class far back in the last century, chemical reactions typically
> double in speed every 7 degrees (F or C, I don't remember). Unlike what
> you read on the net (yeah, it must be true :-), I think at 220F the oil
> life is more like 500,000 miles...
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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: [GMCnet] GmTrans temp [message #155432 is a reply to message #155431] |
Wed, 04 January 2012 19:08 |
Mr ERFisher
Messages: 7117
Registered: August 2005
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Senior Member |
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looks a lot like the table here
http://www.gmcmotorhome.info/CRANKS.html#COOLER
gene
On Wed, Jan 4, 2012 at 4:33 PM, Ken Henderson <hend4800@bellsouth.net>wrote:
> ATF life prediction from the P-30 manual I referenced earlier:
>
> DEGREES F MILES
> 175 100,000
> 195 50,000
> 212 25,000
> 235 12,000
> 255 6,000
> 275 3,000
> 295 1,500
> 315 750
> 335 325
> 355 160
> 375 80
> 390 40
> 415 Less than 30 Minutes
>
> Temperature as measured in the pan.
>
> Ken H.
>
>
>
> On Wed, Jan 4, 2012 at 6:16 PM, Gary Casey wrote:
>
> > John,
> > I think that is something like what happens, but as I recall from a
> > chemistry class far back in the last century, chemical reactions
> typically
> > double in speed every 7 degrees (F or C, I don't remember). Unlike what
> > you read on the net (yeah, it must be true :-), I think at 220F the oil
> > life is more like 500,000 miles...
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html
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| Re: [GMCnet] GmTrans temp [message #155433 is a reply to message #155432] |
Wed, 04 January 2012 19:22 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
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Isn't there some kind of a time frame that goes with these temperatures? I would think half an hour at 220 degrees would be a lot different then 30 seconds at 230 degrees then down to 150 degrees operating temperature.
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: [GMCnet] GmTrans temp [message #155440 is a reply to message #155433] |
Wed, 04 January 2012 19:56 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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| roy1 wrote on Wed, 04 January 2012 18:22 |
Isn't there some kind of a time frame that goes with these temperatures? I would think half an hour at 220 degrees would be a lot different then 30 seconds at 230 degrees then down to 150 degrees operating temperature.
|
Absolutely Roy--that's missing from this discussion. I can tap the burner on my stove momentarily and not burn my finger. I fully expect fluid temperatures to rise and fall based on immediate power demands but it is the long term steady state temperatures that matter.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] GmTrans temp [message #155454 is a reply to message #155431] |
Wed, 04 January 2012 21:20 |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Ken
I have a copy of that manual. If I recall it is over 20 years old.
There have been many changes in transmission fluids over those years.
The modern fluids, especially the 100% snythetic ones such a Mobil 1, will last many times what the table says.
Emery Stora
On Jan 4, 2012, at 5:33 PM, Ken Henderson wrote:
> ATF life prediction from the P-30 manual I referenced earlier:
>
> DEGREES F MILES
> 175 100,000
> 195 50,000
> 212 25,000
> 235 12,000
> 255 6,000
> 275 3,000
> 295 1,500
> 315 750
> 335 325
> 355 160
> 375 80
> 390 40
> 415 Less than 30 Minutes
>
> Temperature as measured in the pan.
>
> Ken H.
>
>
>
> On Wed, Jan 4, 2012 at 6:16 PM, Gary Casey wrote:
>
>> John,
>> I think that is something like what happens, but as I recall from a
>> chemistry class far back in the last century, chemical reactions typically
>> double in speed every 7 degrees (F or C, I don't remember). Unlike what
>> you read on the net (yeah, it must be true :-), I think at 220F the oil
>> life is more like 500,000 miles...
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] GmTrans temp [message #155479 is a reply to message #155421] |
Wed, 04 January 2012 23:34 |
RadioActiveGMC
Messages: 1020
Registered: November 2010
Location: Hot AZ desert
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I know your much more experienced then me so forgive the question. But does it tend to weep more then non syn? Whats the advantage?
***"Gettin There"-1973 23' Sequoia-
Michael, Onans smell, "Go solar/wind power!"
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| Re: [GMCnet] GmTrans temp [message #155484 is a reply to message #155440] |
Thu, 05 January 2012 02:35 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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| Bob de Kruyff wrote on Wed, 04 January 2012 19:56 |
| roy1 wrote on Wed, 04 January 2012 18:22 |
Isn't there some kind of a time frame that goes with these temperatures? I would think half an hour at 220 degrees would be a lot different then 30 seconds at 230 degrees then down to 150 degrees operating temperature.
|
Absolutely Roy--that's missing from this discussion. I can tap the burner on my stove momentarily and not burn my finger. I fully expect fluid temperatures to rise and fall based on immediate power demands but it is the long term steady state temperatures that matter.
|
You are measuring at the pan. That temp is not going to cool down quickly. You have several quarts of oil plus all of that mass of aluminum and steel to cool down.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
[Updated on: Thu, 05 January 2012 02:36] Report message to a moderator |
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| Re: [GMCnet] GmTrans temp [message #155509 is a reply to message #155484] |
Thu, 05 January 2012 08:20 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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""You are measuring at the pan. That temp is not going to cool down quickly. You have several quarts of oil plus all of that mass of aluminum and steel to cool down.
[Updated on: Thu, 05 January 2012 01:36]
""
Understand but I'm talking sustained operation at elevated temperatures, not temporary spikes of 10 to 20 minutes.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] GmTrans temp [message #155511 is a reply to message #155421] |
Thu, 05 January 2012 09:00 |
RadioActiveGMC
Messages: 1020
Registered: November 2010
Location: Hot AZ desert
Karma: 0
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Not a scientific answer (lol) but whats the advantage of the syn trans fluid? Reason I ask is if I opt to get a new fan might as well change the fluid. Currently it prob only has 1500 miles on fresh fluid.
***"Gettin There"-1973 23' Sequoia-
Michael, Onans smell, "Go solar/wind power!"
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| Re: [GMCnet] GmTrans temp [message #155525 is a reply to message #155484] |
Thu, 05 January 2012 11:32 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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Ken my world out here is different from your world. After climbing a mt. the temperature drops rapidly on the down grade i'm sure the external cooler is a big help also.
Roy Keen
Minden,NV
76 X Glenbrook
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