Stock Temp Sensor Accurate?

[Ed Blown Vert]

Got the car back on the road. But tranny temps show high in EFILive.
The stock tranny sensor reads around 225 after a short cruise. Engine coolant is 200.
I hit the tranny pan with a laser and it reads about 197. Laser on the tranny cooler was about 156.

Is the pan reading accurate?

[JaycenK]

how deep is the pan? It's close but I could see it being off by several deg.

[Ed Blown Vert]

Stock pan

[0rion]

how big is your cooler and is it ran through the stock cooler first then to the aftermarket cooler? I would believe that sensor temp before I did the pan temp for the simple fact that the pan is aluminum and is gonna dissipate heat pretty quickly.

Another couple of thoughts..... is that stop and go and have you got the car up to speed like on the freeway to see if the temps come down? Hard for that tranny cooler to do it's job in stop and go traffic or when it's not getting enough airflow across it to really bring the temps down. Where is your cooler mounted?

[0rion]

derale and permacool also make some bad ass coolers with built in fans. That'll be what I go with the next time. I think their max gvw isn't way above the non-fan versions (jeg's bigger version lists it at 30,000gvw) but it's the fact that fan will run when you're at stoplights or in the staging lanes where the traditional non-fan coolers aren't doing much.

[Ed Blown Vert]

how big is your cooler and is it ran through the stock cooler first then to the aftermarket cooler? I would believe that sensor temp before I did the pan temp for the simple fact that the pan is aluminum and is gonna dissipate heat pretty quickly.

Another couple of thoughts..... is that stop and go and have you got the car up to speed like on the freeway to see if the temps come down? Hard for that tranny cooler to do it's job in stop and go traffic or when it's not getting enough airflow across it to really bring the temps down. Where is your cooler mounted?

I run the B&M 24k cooler. And in the past there were no issues with temps. Even when I sent the tranny in for a check-up. Guy said the tranny was in excellent condition.

The temps are when I am on the freeway. They may go down a few degrees. Its mounted just in front of the condos on the passenger side. Stock cooler is in-line.

I wonder if the stock sensor went bad?

[0rion]

when you say the fluid is 200, was that shot right off the dipstick with the laser? Even 200 is too hot really. You could always put a mechanical temp gauge in the line somewhere to verify your temps but it sounds like the temp's are just up. Not sure why that would be. Is that a freshly rebuilt tranny? Maybe performabuilt will chime in with some thoughts.

[Ed Blown Vert]

Engine coolant is 200.

Tranny wasn't rebuilt. The builder said it didn't need rebuilding.
You don't think the laser is correct?

[0rion]

I just don't trust the pan to give you an accurate reading of the fluid inside due to the heat dissipation from the aluminum pan. I bet that sensor is closer to being right than the pan but that's a guess. If you don't trust the sensor then the next step is to probably put a mechanical gauge on it. Maybe yank that dipstick and shoot the fluid right on the stick and see what it says.

[Ed Blown Vert]

I guess I can try that.

I'll take a look at a temp sensor. I can pull the drain plug and install it there.

[pajeff02]

I also use a laser to verify temperature readings on our vehicles. I would shoot the transmission at the fitting where the fluid is exiting the transmission on its way to the cooler. That should give you the most accurate read on fluid temp.

[Ed Blown Vert]

I'll try that.

I am wondering if it is the correct temp. If my converter is the problem. The tranny checked out ok, but didn't check the stall.

[thearborbarber]

On the 4L60e's on the pickups the temp sensor reads the fluid coming out of the converter. I have to assume it's in the same location for the cars as well.

[Ed Blown Vert]

On the 4L60e's on the pickups the temp sensor reads the fluid coming out of the converter. I have to assume it's in the same location for the cars as well.

If its reading it from the converter, its going to show alot higher temps.

[Smittro]

Imho, it's prolly not something to worry about. It's prolly accurate as it needs to be for your tune to function properly. But if you're worried about a possible sensor issue, for all the more they cost I'd go grab the one you thing it maybe or all of them and see if there's a change @ the guage. For best accuracy with your lazer, I'd do as Jeff (excellent idea fittings collect heat do to their slight restriction of flow) suggested or get her up to temp and use a suction(sp) tool to pull some tranny fluid out of the dipstick tube then laze it there. I would also consider (if you're that concerned) buying as Orion stated a cooler or a set of coolers that have built on cooling fans.. Cooler trans temps generally= long life in auto's but I guess you know that already.. Just my .02..

[Cutlass]

Here's a little info for you from the GM Service manual for a 2000 LS1 Camaro.

The flow of transmission fluid starts in the bottom pan and is drawn through the filter, control valve body assembly, transmission case and into the oil pump assembly. The oil pump assembly pressurizes the fluid and directs it to the pressure regulator valve where it becomes the main supply of fluid to the various components and hydraulic circuits in the transmission. Hot fluid exiting the torque converter flows through the converter clutch apply valve and into the transmission cooler lines to the oil cooler located in the vehicle radiator (and auxiliary cooler if equipped). From the cooler, fluid returns to cool and lubricate the front of the transmission. In forward drive ranges, D4 fluid from the manual valve is routed through an orificed cup plug in the rear of the transmission case to feed the rear lube fluid circuit.

[Ed Blown Vert]

Drove it to work today. When I got home. The Tranny temps were 226. Engine coolant was 200
Pulled the dipstick and hit the fluid the best I could with the laser. 180-190

[0rion]

that sounds more normal.....maybe that sensor is reading wrong.

[Ed Blown Vert]

I am thinking the same thing.
I'm going to install a 160 thermostat and that should drop the temps a bit.
And then just drive it.