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This might be long but I would like some help. I've been having trouble with my trans the last couple of days. It started when I bombed through a snow drift and didn't realize I had packed my trans cooler full of snow. Later that night I was pulling the skid steer to go plow and my trans pegged out my 250 degree gauge. Before that incident my trans would always run about 235 while pulling the skid steer and right around 150 empty. Since then I run 210 empty and over 250 pulling.
I put a code reader on my truck and it retrieved a 741 code for torque converter clutch stuck on. I took the truck to the shop that rebuilt it last year (diode failure thanks ford) and they replaced the sensor for the ebpv and cleaned the tube, they thought that could cause the computer to tell the converter to lock. They also said there is a pcm update that addresses this issue and I need to go to Ford for this. But I'm pretty sure the dp tuner will overide the pcm. Anyway I think it might be a hard part problem and not a software problem since it never happened before the trans cooler got blocked, and yes I have cleaned it out. Any ideas? Thanks
Do an Advanced Search and some reading on "Transmission Bypass Valve". It seems a failure of this valve can result in higher temps. I'm guessing you already have, but take a good look at all the lines and make sure the snow bomb didn't kink a line somewhere. How does the fluid smell? Burnt? Hopefully not... If so, you'll need do a fluid change and see where you're at.
My bypass valve failed last year. It was not expensive and easy to replace. The dealer told me not to replace it as they have never seen one go bad. My symptom was I would run hot, then fine for a few days, then hot and it would keep cycling. It seemed the colder it was outside, the hotter the tranny was.
Thanks for the replies. I drove my truck 8 miles today pulling 14,000 lbs and the trans walked right up to 250 degrees. I crawled underneath and just felt the lines. Of the the two lines going to the cooler, one was hot and the other was warm. So i assume it is partially cooling some fluid. The bypass line felt as hot as the line going to the cooler. What is the temp supposed to be for the bypass? Thanks.
Not sure?? You might try to PM Mark Kovalsky, he was an 4R100 Tranny engineer and might be able to help.
If memory serves, the tranny will take 220F all day long, but only brief excursions to the 250F range. I'd be scared to operate at all at 250F considering you are risking a $5k+ transmission.
I'm not sure I understand the code. TC Clutch stuck on to me means locked, which it can't be, obviously. Now if it's UNLOCKED all the time, then your on to something, and would certainly lead to high temps. But I'd get nervous running mine over 230. If yours is running 250+, something bad has happened, I'm afraid. And it'll probably only get worse. Have you smelled your fluid yet?? I'd be willing to bet it smells a little burnt...
The temp sender is in the port on the drivers side of the trans. The fluid smells a little burnt and is going in tomorrow to get changed. I talked to the guy that rebuilt the trans last year and he said he used the updated bypass line. He is thinking either a blocked cooler, inline filter or bad bypass valve. Any other thoughts?
On a side note a friend of mine priced out a new trans from Ford for $2700 with a 75kmile warranty. But after having it built last year I hope I don't have to go down that road.
Well, they did some testing and they think the air to air cooler is the main culprit. The lines coming out of the trans flow 2 gallons per minute. Going through the radiator cooler it drops it down to 1.2 gpm, after the stock air to air cooler it's only .5 gpm. They said it was easiest to replace the whole radiator at $371, and an air to air cooler for $255.
For now I told them to put on the air to air cooler on. I think I can find and change the radiator for less money.
One thing is for sure the next truck will have a manual trans, these autos are nothing but trouble.