Low Transmission Temp
Thread Starter
Heel & Toe
Joined: Jul 2024
Posts: 23
Likes: 34
From: Columbia SC
Low Transmission Temp
Hello all!
I am about 1100 miles into my C8 in 75 days, we've had a lot of rain and just avoiding the cleaning by not driving it in the rain.
My curiosity is what looks like low trans temps because my limited knowledge is that you need enough temp to keep oils healthy and get rid of any moisture even if it shouldn't be there. It's been 90-95 degrees here, so plenty hot, and I have only seen 175 one time and then it dropped to 160 within 2 minutes of steady state driving. Yesterday at 95 degrees ambient I had water 189, oil 181, trans back to 156 2 minutes after coming off some spirited highway driving. Stop and go city, in the heat, tends to be 150ish at most. I haven't seen oil over 185 either. Does this car just have so much cooling capacity that without totally thrashing the trans doesn't get to the 180-200 range claimed to be "normal" via Google?
Is that too low?
I am about 1100 miles into my C8 in 75 days, we've had a lot of rain and just avoiding the cleaning by not driving it in the rain.
My curiosity is what looks like low trans temps because my limited knowledge is that you need enough temp to keep oils healthy and get rid of any moisture even if it shouldn't be there. It's been 90-95 degrees here, so plenty hot, and I have only seen 175 one time and then it dropped to 160 within 2 minutes of steady state driving. Yesterday at 95 degrees ambient I had water 189, oil 181, trans back to 156 2 minutes after coming off some spirited highway driving. Stop and go city, in the heat, tends to be 150ish at most. I haven't seen oil over 185 either. Does this car just have so much cooling capacity that without totally thrashing the trans doesn't get to the 180-200 range claimed to be "normal" via Google?
Is that too low?
Race Director
Joined: Mar 2007
Posts: 11,258
Likes: 8,389
Hello all!
I am about 1100 miles into my C8 in 75 days, we've had a lot of rain and just avoiding the cleaning by not driving it in the rain.
My curiosity is what looks like low trans temps because my limited knowledge is that you need enough temp to keep oils healthy and get rid of any moisture even if it shouldn't be there. It's been 90-95 degrees here, so plenty hot, and I have only seen 175 one time and then it dropped to 160 within 2 minutes of steady state driving. Yesterday at 95 degrees ambient I had water 189, oil 181, trans back to 156 2 minutes after coming off some spirited highway driving. Stop and go city, in the heat, tends to be 150ish at most. I haven't seen oil over 185 either. Does this car just have so much cooling capacity that without totally thrashing the trans doesn't get to the 180-200 range claimed to be "normal" via Google?
Is that too low?
I am about 1100 miles into my C8 in 75 days, we've had a lot of rain and just avoiding the cleaning by not driving it in the rain.
My curiosity is what looks like low trans temps because my limited knowledge is that you need enough temp to keep oils healthy and get rid of any moisture even if it shouldn't be there. It's been 90-95 degrees here, so plenty hot, and I have only seen 175 one time and then it dropped to 160 within 2 minutes of steady state driving. Yesterday at 95 degrees ambient I had water 189, oil 181, trans back to 156 2 minutes after coming off some spirited highway driving. Stop and go city, in the heat, tends to be 150ish at most. I haven't seen oil over 185 either. Does this car just have so much cooling capacity that without totally thrashing the trans doesn't get to the 180-200 range claimed to be "normal" via Google?
Is that too low?
The transmission cooler is actually a heat exchanger with the engine coolant, so its temperature can be affected by by engine coolant temperature. I don't look at the temperatures that much, but when I do I typically see them close to each other.
There are a ton of DTC associated with the transmission fluid temperature sensors. It looks for all sorts of conditions. It checks for difference between the fluid temperature and the coolant temperature being too large, overtemp conditions, out of range conditions, and circuit issues - short to ground, short to voltage, and open circuit. The point is, if you have an issue you will likely have a DTC set. But it might not cause a CEL on the DIC.
Race Director
Joined: Aug 2016
Posts: 12,710
Likes: 10,140
From: Garden Valley CA
According to the Service Manual, the normal operating temperature for the both transmission fluid temperature sensors is between 122 deg F and 212 deg F. Of course you would expect to normally see temps that others are seeing - I get that. But unless you are seeing a CEL or have a DTC, or behavioral issues with the car, you probably have no problem. There are DTCs that can be set that will not generate a message on your DIC, so your dealer could check for that.
The transmission cooler is actually a heat exchanger with the engine coolant, so its temperature can be affected by by engine coolant temperature. I don't look at the temperatures that much, but when I do I typically see them close to each other.
There are a ton of DTC associated with the transmission fluid temperature sensors. It looks for all sorts of conditions. It checks for difference between the fluid temperature and the coolant temperature being too large, overtemp conditions, out of range conditions, and circuit issues - short to ground, short to voltage, and open circuit. The point is, if you have an issue you will likely have a DTC set. But it might not cause a CEL on the DIC.
The transmission cooler is actually a heat exchanger with the engine coolant, so its temperature can be affected by by engine coolant temperature. I don't look at the temperatures that much, but when I do I typically see them close to each other.
There are a ton of DTC associated with the transmission fluid temperature sensors. It looks for all sorts of conditions. It checks for difference between the fluid temperature and the coolant temperature being too large, overtemp conditions, out of range conditions, and circuit issues - short to ground, short to voltage, and open circuit. The point is, if you have an issue you will likely have a DTC set. But it might not cause a CEL on the DIC.
Race Director
Joined: Mar 2007
Posts: 11,258
Likes: 8,389
You're right though, moisture was one of the reasons for the three year change given by a GM rep. The other was the additive package.
Race Director
Joined: Aug 2016
Posts: 12,710
Likes: 10,140
From: Garden Valley CA
Could be. Of course, most don't see it that low (122 deg) after warm up. Its why I commented that one would expect to see what others are seeing normally. The numbers in the Service Manual that are defined as "normal" , not limited to temperature ranges, often seem to be beyond the range most of us actually see. I think even the OP's temps were not that low.
You're right though, moisture was one of the reasons for the three year change given by a GM rep. The other was the additive package.
You're right though, moisture was one of the reasons for the three year change given by a GM rep. The other was the additive package.
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Race Director
Joined: Mar 2007
Posts: 11,258
Likes: 8,389
"Transmission Fluid Temperature Sensor
Operating Conditions: Engine = Running
Parameter Normal Range: 50 to 100 °C (122 to 212 °F)"
The statement for Transmission Fluid Temperature Sensor 2 is the same.
It also gives the sensor reporting range, and its much lower and much higher than that stated normal range.
Drifting
Joined: Feb 2023
Posts: 1,353
Likes: 1,115
Hello all!
I am about 1100 miles into my C8 in 75 days, we've had a lot of rain and just avoiding the cleaning by not driving it in the rain.
My curiosity is what looks like low trans temps because my limited knowledge is that you need enough temp to keep oils healthy and get rid of any moisture even if it shouldn't be there. It's been 90-95 degrees here, so plenty hot, and I have only seen 175 one time and then it dropped to 160 within 2 minutes of steady state driving. Yesterday at 95 degrees ambient I had water 189, oil 181, trans back to 156 2 minutes after coming off some spirited highway driving. Stop and go city, in the heat, tends to be 150ish at most. I haven't seen oil over 185 either. Does this car just have so much cooling capacity that without totally thrashing the trans doesn't get to the 180-200 range claimed to be "normal" via Google?
Is that too low?
I am about 1100 miles into my C8 in 75 days, we've had a lot of rain and just avoiding the cleaning by not driving it in the rain.
My curiosity is what looks like low trans temps because my limited knowledge is that you need enough temp to keep oils healthy and get rid of any moisture even if it shouldn't be there. It's been 90-95 degrees here, so plenty hot, and I have only seen 175 one time and then it dropped to 160 within 2 minutes of steady state driving. Yesterday at 95 degrees ambient I had water 189, oil 181, trans back to 156 2 minutes after coming off some spirited highway driving. Stop and go city, in the heat, tends to be 150ish at most. I haven't seen oil over 185 either. Does this car just have so much cooling capacity that without totally thrashing the trans doesn't get to the 180-200 range claimed to be "normal" via Google?
Is that too low?
Melting Slicks
Joined: Aug 2000
Posts: 2,391
Likes: 1,166
From: Early 2020 Z51 Coupe, Original Owner, Ahwatukee Foothills, AZ