How high is safe in the line then?

 

You won't believe me, but in my opinion it's 300°F.

 

Hmmm that seems way high for my liking. I guess I'll see what kind of temps it runs at around 55 on a flat highway, and go from there.

 

Your right, we should not believe you. At 300 degrees the fluid should be trashed in about 1500 to 2000 miles

The effect is cumulative. Short term exposure to high heat levels (or even prolonged exposure to moderate heat) can break down the oil to the point where even very short episodes of overheating will lead to failure.

The issue is that letting the fluid reach that temp, does the damage.

Try to keep it around the low 200ish degrees or so, and adding a large cooler after the fluid comes out of the radiator should help drop it well below engine temp so when it goes through the trans it has some thermal cushion to heat back up to engine temp.

 

You're the trans expert. I will leave this to your expertise.

 

well mark, you seem to be the expert on trannies, so please, tell us why you're right. personally, i've never had a trans temp gage (though i should)... i haven't studied this enough to form an opinion, so i want your explanation, and plan to install a trans temp gage sometime this year, along with an EGT gage

 

Mark you need to introduce yourself and put this "who da expert?" thing to rest!

Mark might be a bit modest but for you newbies he was a Ford trans engineer for something like 22 years-----not bad credentials huh? His reputation and contributions here in FTE aren't idle chatter, speculation or thoughts that come to him in a dream---he knows his do do!

If/when Mark K says something about a trans y'all might wanna pay attention----jus' sayin'..........

 

I was a Ford automatic transmission engineer and engineering supervisor from 1988-2007. During my career I worked on calibration (the "chip"), OBDII, and transmission cooling.

The out line from the trans is the output of the torque converter. This is the hottest part of the trans.

When the torque converter is unlocked, and in a C6 that's all the time, the torque converter makes A LOT of heat. If the trans is working hard it makes even more heat. Temperatures out of the torque converter can easily reach 300°F. That's why there is a cooler, so that the pan temperatures stay where they belong, below 220°F.

If you see temperatures up to 300°F in the line to the cooler, the only thing you can do to lower that temperature is reduce the load on the trans. Adding more cooling will have a minimal effect on this temperature. It will lower the pan temp, but it won't reduce the work the torque converter is doing, and work causes heat.

Those people that believe that ATF is trashed in 1500-2000 miles at 300°F are reading a chart that has been floating around the internet since there was an internet. It was outdated when the internet was invented, but that doesn't stop people from quoting it as gospel. I'm sure it was accurate back in the 60's, but fluid technology has inproved quite a bit since then. Modern fluids can tolerate 300°F for a long, long time.

You are, or course, welcome to believe me or not.

 

How good would a inline temp sensor work, in the RETURN cooler line (from cooler, back to trans)?

Would that give about the right "pan temp" without actually drilling the pan and having a sensor there?

 

No, it's cooler than the pan. The pan also gets fluid that falls from higher in the trans, so it has a mix of cooled and non-cooled fluid.

 

So, in your opinion, the best location for the addition of a Temp Gauge would be in the pan itself rather than a line location?

Trying to get one lined up for my 85 but want to ut it where it will provide the best information in regards to true temp.

Thanks.

 

If there is no test port then the pan is the next best option.

 

Well I'm REALLY confused now.

Mark,
Are you saying it's ok to use a test port ?
Is there a test port on an 87 C6 ?
If not, do you know the best place on the pan to weld a bung?

 

Best place IS a test port.

However, all C6's DON'T have a test port, so next best thing is the pan.


X2, where is the best place on a pan...if any?

 

I agree.

I don't know. I never worked on a C6. I can tell you that you need to install it where it won't hit things inside the pan. Also, temperatures vary quite a bit inside the pan. I've often measured more than 20°F difference from hottest to coldest spots in the pan. I don't know where the hot and cold spots are in a C6.