The transmission cooler does two things... first, it warms the fluid
as the engine comes up to temperature, then it cools the fluid as the
transmission is worked.
Hydraulics are a funny thing.... If the fluid is too cold or too hot,
the transmission does not operate properly and its longevity suffers.
Most times, the temperature in the radiator is kept in the 175 to 210
degree F range... this is optimal for a transmission to function
properly. The transmission WILL build much higher temperatures when
under extreme loads.
A GOOD aftermarket transmission cooler that mounts ahead of the heat
of the radiator will be thermostatically controlled and will by-pass
when the fluid temperature is too low. If you drive very
conservatively on a cold day and are only using an auxilary
transmission cooler without a by-pass, the transmission will suffer.
On 17 Nov 2006 18:05:08 -0800, " firstname.lastname@example.org"
The fluid lines on a water cooled trans are tapped from the front
pump circuit and runs through a coil in the lower radiator tank.
Obviously if the radiator temp is maintained around 180, then the trans
fluid will be either heated up to or cooled down to that temp.
The temp sender for a trans should always be placed,somewhere, in the
pan. Purolater sells a remote trans filter setup with a temp sender
option, but the fluid lines from the trans always come from the
converter through the front pump and are hotter than the actual trans
temperature. When the fluid is returned from the cooler, it's dumped
over the drums and gearsets, which drains into the pan, so your actual
temperature sample is better taken from there.
Interesting explanation. The '64 Champ I had until it was totaled in '83
had a Powershift tranny. It had the water-cooler radiator, but I added
another transmission oil cooler through which the oil went before reaching
the radiator. One winter (snowing and about 20 degrees) I was pulling a
14-foot cargo trailer loaded with two dealer stocks of parts and I couldn't
get it to shift from 2 to 3 until I had driven maybe a 100 miles. Maybe I
was keeping the fluid too cool.
When I rebuilt the HFH, I discovered that the transmission lines went to the
lower portion of the radiator.
The two ports looked to have been re"brazed" over. There was no sensor in so
far as to regulate the temp of the fluid, that I could see.
I read a lot about the metal that divides the coolant section from the
transmission fluid failing over the years so
I added an external cooler ahead of the radiator, and have not had problems.
I would love to find a method to determine both oil temp and fluid
temp.There was a service bulletin for the Ultramatic that was titled.
Transmission does not shift properly at operating temerature.
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