Auto. Transmission Temperature Parameters When Towing

We've towed all over BC, this is a regular kind of trip;


Not exactly flat.. I tow in S4, with ECT on, and can stay at 90kmh easily. Coolant and Transmission Temps stay around 90C (194F) steady. When I climb it goes into 3rd and temps slowly rise, they have always peaked at 110C (230F) and stayed there until the top of the hills. Gas mileage is pretty lousy when the trailer is on 9-11mpg is not unusual.. But its hard to beat the view when you get there;

 

And your truck does not have any aftermarket trans. fluid cooling equipment, correct?

 

Stock OEM transmission cooler from the towing package only.

 

This is what happens when it is 18 F outside. 15 mile commute at 65 mph . Don’t need to pin the t stat open. Did the screen shot at the stop light after getting off the freeway. Barely warm.

 

I agree for that drive you don't need to pin it open. the reason i'm pinning mine open is for long drives up to the sierra's towing or unloaded. I would see torque converter temps up in the 220 range even unloaded at times when shifting down to third. Pinned open i never see pan temp get over 170!

 

The problem I’ve seen with revving up around 3500 or more is the heat. The oil temp - which heats up the tranny fluid through the internal reservoir- gets above 200 pretty fast anytime
I’m revving the engine into the powerband. The tranny temps
would be fine if the oil temp was more under control. But the oil is 100% synthetic so it can handle those temps. I wish the tranny tstat would bypass the internal reservoir when engine temp is above tranny temp.

 

Oil temp? As in engine oil temp? Do u have a 3rd party temp sensor? Tacos don’t have one, more than like calculated off other PIDs. I didn’t know the engine oil temp and trans oil were coupled in any way. I only knew of the trans and engine coolant.

 

Yeah I think it is calculated from the coolant sensor. The tank for tranny fluid that is inside the radiator - in my experience - keeps the two temps
Close when the tranny tstat is open. So - when the engine is revving high the radiator temp goes up and the Tranny temp with it. Those in warm
Climates remove the radiator tank from the tranny system and avoid this issue. Being in a cold climate I leave it in place.

 

The ScanGuage II we installed in our 2016 Taco shows engine crankcase oil temperature. I'm not versed as to if there is a dedicated sensor for the engine oil temp. but I always assumed there is. Regardless of where the engine oil temp. info is coming from it consistently runs within a degree or two of the trans. oil pan temp.

Just an update after a full summer of towing our 5000 lb. deck boat & trailer last year and half of the summer this year. The Taco handles the boat & trailer with relative ease here in flatland Illini Country. We even pulled the boat to Table Rock Lake from central Illinois. On I-44 through the Ozark Mountains I ran in S4 with ECT engaged and our Taco would regularly shift down to S3 but only momentarily. With the trans. T stat pinned open our trans. temps. ran from 165° F on the low side and the hottest we saw in the mountains was 195° F on the high side. That's with the cruise set at about 67 MPH. The Taco gave a very good account of itself. We were impressed and quite happy with how it handled the boat!!

 

anyone tried a thermostat that opens at a lower temperature?

 

this thermostat opens at 140 degrees:

https://www.rockauto.com/en/moreinfo.php?pk=12965709&cc=3354142&pt=2200&jsn=891

OEM is 180 degrees.

 

Agreed. The engine and trans temps seem to rise and fall with each other, when the trans tstat is open. One of these days I need to bypass the rad.

 

For what it's worth my Tacoma's ATF has never exceeded 195F unloaded and I've been up and down several mountain passes here in CO. That's measured with scangauge 2. Normal temps read 165-170.

 

mine hits 200 in traffic when its hot. that's the pan temp. it's even worse going up and down mountains (seen up to 210). need to get aux trans cooler for my 2.7

 

My experience is very different. I get to 200 driving homE from town up my driveway. Yeah it’s a hill - but jeez 200 degrees for 20 min ride?

 

Would you recommend this kinda setup if you have a heavier overland truck?

 

Nah. Go plate and fin with the name brand guys, Hayden B&M etc.