Is there any risk of mechanical failure or other detriments resulting from running a mechanical transmission at low temperatures?

The transmission in question is connected to the vehicle's coolant loop via an oil/water heat exchanger. The coolant was originally at 80-110 degrees, but will now be in the 10-40 degree range. Inside the transmission there are a number of gears that are always in mesh. Gear selection is done by activating one of several internal clutches. The clutches are controlled by internal solenoid valves. The gear shafts are hollow and cooled by circulating oil through them. Inside the transmission there is also a hydraulic pump, filter, and relief valves. Finally there is also a torque converter, which will be removed. The original transmission oil type will be kept.

  • 2
    $\begingroup$ I'm assuming the temperatures you specify are Fahrenheit, not Celsius. It would be useful if that was specified. $\endgroup$
    – Fred
    Commented Dec 7, 2023 at 9:17
  • $\begingroup$ read the user manual ... or ask the transmission manufacturer ... they know what the operating parameters are $\endgroup$
    – jsotola
    Commented Dec 7, 2023 at 19:32
  • $\begingroup$ @jsotola We know what the operating parameters are. $\endgroup$
    – K0ICHI
    Commented Dec 8, 2023 at 2:26
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    $\begingroup$ @jsotola, ... but we're not going to tell you whether it is °F or °C. That information isn't for sharing. $\endgroup$
    – Transistor
    Commented Jan 7 at 14:29
  • $\begingroup$ The only issue I can think of is that the viscosity of the lubricant will change. $\endgroup$
    – Drew
    Commented Jan 8 at 16:27

1 Answer 1


If the coolant is between 10-40 degrees, then the engine will be operating at too low a temperature.

For the transmission that may not be such a problem.


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