towing questions

[normaltype]

Question about transmission oil and oil temps.

Anyone know where the trans oil temp sensor is located? Sump or Converter outlet (precooler)?

Reason I ask is it makes a difference as to what oil temp readings I will recieve.

I got the transmission oil up to 198F on the weekend, it was pretty hot out. Scared the crap out of me because someone here says don't go over 200. So i did some research.

What I've found is that 180F is normal operating temp and for each 20 Degree increase the oxidation rate of the oil doubles up to 300F (+- a few) is when metal warps and damage will most certainly occur.

So a 200F max transmission oil temp is not unrealistic as long as they are not for a prolonged period of time. So for example, a long hill climb (5 minutes) with temps reaching max 240F then cool back down would not be unreasonable and would only mean the life span of the oil has been shortened.

Just means more frequent oil changes. Which makes sense.

Also, a possible good tip i found is that because the oil cooler relies on foward motion (air flow) to cool the oil, simply pulling over is not enough you must idle at 1200rpm to engage the cooling(coolant) fan. Anybody hear this tip before? Does it make sense? I'm not familiar with the fan system on the Explorer so I'm not sure it would apply. Might be something to keep in mind.

PS i've tried my trailer with and without anti-sway and the anti-sway DEFINATELY makes a difference on 5000-6000lb trailer. Not realistic for short hauls or city driving. But long highway hauls over and hour its a definate bonus.


Looking forward to your replies. THanks!

 

[Ronin8002]

I believe the temp sensor is located in the solenoid body, so I THINK it reads temps in the pan (pre-converter temps). I have the shop manual at home and can look this up later to verify.

I did say in an earlier post that you shouldn't exceed 200* for extended periods (my opinion based on the fact that fluid starts to break down when you start getting up in the 200's). As you said, when getting it up in the 200's regularly just expect to have to do a fluid change more frequently as a maintenance item since you're exposing the fluid to more severe usage.

I have noticed that with the A/C on the trans cooler gets hotter air going to it since the A/C condensor seems to "pre-heat" the air, so that temp reading is not surprising. That and with the O/D off I am pretty sure that the torque converter stays unlocked...that slippage would contribute to heating the fluid if I am correct on that.
As far as cooling, obviously your fan pulls air through the radiator at idle and not moving, so putting the trans in park and sitting will allow for some cooling. More airflow of course would be seen at highway speeds as you said but cooling might not occur as effectively unless coasting or on flatter terrain.

You could possibly help the fan pull more air (thus helping cooling) by installing a Hayden or Four Seasons severe duty fan clutch. That would help in hot weather and heavy load conditions and at about 50 bucks might be worth trying. Your mileage will take a hit from the clutch being engaged more fully but you could swap in the OEM one in cooler weather.

I'll take a look in my trans manual when I get home and see if this is all correct. I'll post up with what I find out later.

Question about transmission oil and oil temps.

Anyone know where the trans oil temp sensor is located? Sump or Converter outlet (precooler)?

Reason I ask is it makes a difference as to what oil temp readings I will recieve.

I got the transmission oil up to 198F on the weekend, it was pretty hot out. Scared the crap out of me because someone here says don't go over 200. So i did some research.

What I've found is that 180F is normal operating temp and for each 20 Degree increase the oxidation rate of the oil doubles up to 300F (+- a few) is when metal warps and damage will most certainly occur.

So a 200F max transmission oil temp is not unrealistic as long as they are not for a prolonged period of time. So for example, a long hill climb (5 minutes) with temps reaching max 240F then cool back down would not be unreasonable and would only mean the life span of the oil has been shortened.

Just means more frequent oil changes. Which makes sense.

Also, a possible good tip i found is that because the oil cooler relies on foward motion (air flow) to cool the oil, simply pulling over is not enough you must idle at 1200rpm to engage the cooling(coolant) fan. Anybody hear this tip before? Does it make sense? I'm not familiar with the fan system on the Explorer so I'm not sure it would apply. Might be something to keep in mind.

PS i've tried my trailer with and without anti-sway and the anti-sway DEFINATELY makes a difference on 5000-6000lb trailer. Not realistic for short hauls or city driving. But long highway hauls over and hour its a definate bonus.


Looking forward to your replies. THanks!

 

[badloser]

I just completed a 2000 mile trip towing 6200lbs through the Smokey Mountians in Tennessee with my 04. I never turned on the tow switch and just drove it normal. I had no issues at all.I have the tow package and V8 and am really impressed with this SUV. I towed about 7500lbs and used the tow switch and burned up the fluid so I did a trans fluid change from my local dealer and went on the trip with out using the tow mode. I think a treans temp guage is a great idea.

 

[Ronin8002]

OK so I have confirmed the temp sensor is located in the solenoid block. Still not 100% sure if this is pre- or post- torque converter in terms of fluid flow...though I still think it is probably pre-converter.

I learned something else...with O/D off your torque converter can still lock up. All it does is take away 5th gear and allow engine braking in 4th gear...now it makes even more sense why that mode is recommended for towing (4th gear is a higher ratio than 5th and so you should have more pulling power).

I am going to be installing a deep transmission pan on my truck soon. My hope is that by adding 4 extra quarts of volume, that will help with keeping the average temps lower. The pan is aluminum and there are cooling fins on it so that may help also.

NormalType I still wonder if for your application a severe duty fan clutch might help with the transmission cooling.