I have looked at so many transmission posts and can't seem to find an answer so here we go

2002 F 350 7.3 4x4

Aftermarket gauge will climb to 250° after around town driving of an hour or so or multiple trips within the hour. Not towing. 160,000 miles on odometer. Changed trans fluid at 40,000 mile intervals. Most recently about 1500 miles ago. Most recent change using Mark K's method. Was getting fluid from rear port when I changed fluid. Blew out oil cooler and there did not seem to be a blockage as flow was sufficient. Still overheating according to autometer trans gauge in test port. No codes retreived using autoenginuity also O/ D light is not flashing. Would like to run torque converter slip test using AE according to woodnthings method but TC slip desired and transmission gear ratio is not available under that name in live data meter. AE just updated to most recent version.

I purchased a new tranny oil bypass and will install soon. Also purchased a new 6.0 cooler to replace stocker but am hesitant to install if tranny is failing because I am concerned that the new cooler will just get some blockage from a potentially failing transmission and I will be buying a new cooler along with a BTS rebuild. Any help is appreciated.

Mike

 

First off are you sure that you temp. readings are accurate? Thermocouples can go bad. The old cooler may be plugged/contaminated. I am running a Magnafine filter on mine post cooler as I bought a used one but have zero issues. You could install one ahead of the cooler just in case, but don't use two of them. Many question the use of a filter at all.
Unfortunately heat is generated by slipping parts in most cases.

 

Thanks for the quick reply.

I also thought maybe the gauge or the sensor in the test port is bad but how would one go about checking that. Any thoughts?

 

You have AE? See what the PCM is reporting for transmission temperature.

 

Install the new bypass only. See if that drops temps and flow from rear port. Guessing it will. If so, install new cooler & enjoy.

 

^That's the right answer. ^

Your bypass is almost certainly the problem.

 

What does the bypass look like and where is it located?

 

Part #10 in post #12 of the attached link.

https://www.ford-trucks.com/forums/8...e-routing.html

 

Clearly I'm AE deficient. Thanks for the reminder about checking the temps using AE. I checked them twice today and both times they were spot on with the gauge so I guess that rules out the cheap option.

 

Thats the plan this weekend. Seems pretty simple. Fingers crossed.

 

Thanks Mark. I was hoping that you would chime in. I did run AE for a live session without the missing paramaters that Ken suggested (TC slip desired and gear ratio). Am I right in understanding that there will be significant torque converter slip until TC lockup? At 75 MPH on cruise control today the the TC slip actual was mostly less than 3.0 but there were times when I would see it jump above that 5.0 threshold. The terrain was mostly flat but there were some very mild up and down where I think the truck was adjusting to maintain speed. Would that reflect in TC slippage?

 

Not sure I understand. Were you referring to the post prior to yours regarding the location of the bypass? Thanks.

 

Yes, that's correct.

I don't know what the 5.0 threshold is.

The converter clutch can release in this condition, which will cause the slip to go from nearly zero to a few hundred RPM.

 

No disrespect intended when I said that I hoped Mark would chime in. Thanks to all of the members who have offered assistance. Keep it coming

Mike

 

Thanks again. According to Kens website a healthy TC will have less than 5.0 RPM difference at TC lockup if I am reading that correctly.

Also AE indicated that TC slip before lockup would be as high as 675. It even registered 1227 accelerating on to the highway then it leveled off to below 5 RPM difference. Is that what I should expect or is that as bad as I am hoping it is not?