Giong this weekend to pick up a new trailer. Its about 1k mile trip back. Truck is 5.4 w/factory tow package and Toyer air/exhaust/software pkg. I bought the new Scan Guage which now reads tranny temps.

Great and all but I just realized I don't know what temp is too high for our tranny's. Anyone know what temp I should stay under? Or what is a good operating range? I would like to keep it in overdrive until (or unless) I see the tranny temps go up too much. I've seen about 1-2 mpg better return keeping it in overdrive while towing. With the guage I will be more comfortable doing so now.



Thanks.

 

Check this out: http://www.tccoa.com/articles/tranny/index.html

Excerpt:

"Most AutoGauge gauges include fittings to either be installed into the pan direct, or to use a temp manifold (like a "T" fitting) that would install into the cooler lines that run to the radiator, this is better than the sump since it is the hottest fluid in the trans. And since fluid life is cut in half for every 25 degrees increase in temp about about 170, it's best to know the hottest fluid."

Keeping it around 170 is good - fluid begins to degrade above that ....

 

Whether you use overdrive or not, the key is keeping the torque converter locked up - when it's unlocked this is when the temps go up.

 

Word!! O/D or not has zero to marginal effect on fluid temps. As mentioned, torque converter lock up is key!!

Me personally (based on talking to guys on here and at Amsoil), at 240* I'm pulling over. Anything 210 or under is not dangerous.

 

Ok, so 210 and under is not a concern. Anything over 170 and I am shortening the lifespan of the oil though. If it gets up to 240 there are real problems. Sound about right?

I am thinking I will change the tranny fluid every winter (15-20k). Does that sound about right for a truck that will see a decent amount of towing? Decent meaning ~5k per year with a ~7500lb load.

 

Obviously towing temps are going to greatly depend on ambient temperatures.

Typically when I was towing in Florida in some real heat I would see consistent tranny temps of 185 or so pulling a 20 ft. enclosed car hauler. I think I've seen 190 for awhile when it was over 100 out but only once I think. When I'm just normally driving around I see 145-150.

This time of year I'd be surprised if it hit 180 because it's cooler.

 

Here are a couple of charts that are in line with what I have been told by most tranny shops. Flashpoint is to hot (way up there) and anything below that just defines the life of the fluid. For myself, I try to be sure not to get over 210 sustained but have gotten up to 220 not sustained going over some of the mountain passes here. I would base your fluid change off of what sort of temps you see on average on a few trips. What you are saying is probably about right but all depends on what sort of hills you see, etc. If you are relatively flat land, you shouldn't see those sort of temps.

http://www.txchange.com/heatchrt.htm

http://www.niehoff.com/techtips/trans.html

 

I have been on the lookout for a deep trans pan to help keep the temps down when I start doing hard towing, but have not been able to find one. When I install it, I am going to install an Autometer trans temp gauge to keep an eye on the vitals of the slushbox.

Question is, is there a deep pan out there for these transmissions (mine is an 03 5.4 4x4, not 100% sure which trans it is though)?

 

Deep pans are okay, but an active tranny cooler like this: http://www.troyerperformance.com/cgi...gno=PPI-ATCKIT is more effective.

Also - pretty much not a lot you can do about an unlocked converter heating fluid. Use a good full synthetic fluid, change it often, and get a tuner that reduces the slippage on shifting (which also lowers temps).

 

Synthetic fluid can be run hotter than standard fluid without breaking it down.

 

That tranny cooler is pretty cool. Anybody running it? If so, how simple to install? Or better yet, are there decent directions? I am down in TX and am towing a pretty heavy load so this may be in my future.

 

B&M makes a deep pan for the 4R70W tranny, but I think it only increases capacity by three quarts which to me personally does not justify the cost. A new, bigger cooler is waaaaaaaaaay more effective than a pan that only adds three quarts. Too bad Mag-Hytec doesn't make a pan for the 4R70W. Their pan for the 4R100 adds like an additional eight quarts or something crazy.

 

Trans temps are a bit complex to get a handle on.
First, where is it being measured?
At the output of an unlocked converter, the temps are the greatest depending on buildup time interval.
Measuring in the pan is not as accurate as what is seen at the converter output.
Then consider the cooler temp drop.
Next question is what is the max at the pan, you should see?
If 170 then the converter could be at 240 under some conditions.
The fluid will take temps as high as 240 + but does indeed degrade the longer it runs at those temps.
So gaging from pan temp is a shot in the dark as to what the fluid is really being heated to.
A gauge in the side of the trans is also not much better because it looks at the case temp as well as does not respond as fast as a gauge in the output line from the converter.
Also consider that the fluid goes from the converter to the radiator where it only cools down to the motor coolant temp minus the drop accross the cooler, then an additional drop accross an external cooler depending on size and airflow/ ambient temp before it goes back to the case to lube other functions and picking up additional heat before getting back into the pan.
Those who use a gauge in the converter line often get concerned about the higher reading when continially reading about max temps in the 170 +/- range without consideration for where the temps are being read from.
I have a custon built 4r70w with a low stall converter to help reduce fluid shear, a hi volume fluid pump and perforemance clutches and discs expressely for towing at max gross combined loads and can tell you that on hills in hot summer temps, the fluid out of the converter gets as high as 240 with out breakdown. The cooler is a 24,000 gvw with a fan on it set to come on at 185+/-. I do change fluid more often than normal but that's the price paid to keep an expensive trans in service.
My normal unloaded converter temps are generally in the 148 range depending on the outside temp and what kind of running is being done as to what the trans has to do for lockup and shifting. Remember that the trans has an internal temp sensor the keeps OD locked out at something around 98 or lower so the 148 running temp is only about 50 above that sensor action.
Bottom line, don't get so rapped up in fluid temps as long as you don't start seeing 200 in the pan, then you have to get concerned.

 

Ummmmmm, I don't think so! Not on my truck anyways. My tranny shifts into O/D just fine regardless of temps. Temperature has zero bearing on the operation of my tranny...O/D, converter lock up, etc. Operates completely normal at any temp. I was even concerned about my tranny running too cool after the new cooler install, but after a couple months now of cold weather driving, it has turned out to be a non-issue.

 

Cold start and run temps lock out '''OD'''. You just have not noticed it yet.
If you did not bypass the radiator cooler, the trans won't run too cool because the engine coolant heats the fluid up faster in cold temps or anytime and passes it to your aux cooler.
I doubt your aux cooler can cool down to very low temps in one pass.
The usual temp drop accross a cooler is about 40 degrees +/- depending on ambient and airflow thru the core.
Fluid leaving a radiator at about 185 and dropped another 50 degrees is still about 135 degrees going back into the case and does not hit the pan until it does some other lubeing and cooling, picking up temp rise again before dropping into the pan.
The temp sensor is usually on the bottom of the valve body with the solenoids where is connects to the harness for the shift control leads etc.
Both 4r70w and thr 4r100 have a TFT sensor.
If it is in fault, a code is set for it.
Reference a FORD service disc to find the info on the TFT.