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2007 F150 4.6L 2WD. I just recently replaced my transmission cooler and the lines on the front of the vehicle. On rides approaching an hour in length, I noticed the trans was acting funny and was overheating. That’s why I changed the cooler. HOWEVER, I now suspect that the issue has to do with a small aluminum block-looking connector halfway down the length of the truck where the trans cooling lines meet. There must be a bypass valve inside of that thing that is failing. Can I repair it or replace it? I’d love to not have to take the four lines off to fix it...
This is the part no. A web search will return pricing and availability.
In the past, I've thought about deleting it. Just remove it. Connect the lines with hoses.
In the end, I decided that it was a necessary component. So much so, that on some models that did not come with the bypass valve, Ford recommends installation.
Thanks Fifty150! I should’ve looked around more before I posted, but I’m thankful for your info The valve just got shipped and I’ll post an update soon.
162K miles, trans rebuilt at 115K. New front end cooling lines soon after rebuild, recent trans cooler. I have a very short commute daily and never take long rides. But over the past few months any time I drive for upwards of an hour, the truck makes a whirring sound as if a propeller has turned on, the shifts become weird, and the mileage gauge says something like ‘service trans’. When I ran my BlueDriver Bluetooth scan tool, the trans heat code showed up. This is why once I put new cooler lines and cooler unit in, I thought the only thing left is the valve, which probably has been the culprit all along. Hope that helps!
Roughly 50,000 miles on the rebuilt transmission. Off the top of my head, I would suggest that you exchange the fluid. No matter what they say about "lifetime" fluid. ATF should be exchanged every 30,000 miles. But 50,000 is usually not enough to make the ATF unusable.
I would also suggest checking to see if your transmission is still under warranty. Who did the rebuild? Was it a 50,000 mile warranty, and now you're at 50,000?
It would help to know what the temperature actually is when it's supposedly high. But not really. Assume that it is really high. Too high. That's why you're getting a dashboard message to service the transmission.
When you say that you replaced the lines, what lines did you actually replace? Cooling line goes from the transmission, to the cooler bypass valve, then the upper inlet at the radiator. Which is usually "good enough" to cool the fluid. At the radiator's lower outlet, the return line will go to the auxiliary cooler (if you have one), the cooler bypass valve, and finally back to the transmission. The ATF is cooled via heat exchange with the radiator fluid. This will bring the temperature down to whatever the temperature is at the radiator. When equipped, additional air cooling is done with the auxiliary cooler.
Keep in mind that there could be more than 1 reason why your transmission is overheating. Is the fluid level correct? Is the fluid contaminated? There could be a blockage anywhere in the cooling circuit. There could be blockage in the radiator. With the right equipment, you could flush the lines, and the fluid cooling circuit. There could be a blockage at the radiator preventing hot fluid from flowing out, and/or cool fluid flowing back in. There could be an internal problem preventing hot fluid from flowing out.
I would service the transmission first. Exchange the fluid. You can do it yourself. You can do it at a dealership. You can find an independent shop. But nothing will work if you don't exchange the fluid. There are plenty of videos that you can find on YouTube related to the 4R70 and 4R75 transmissions.
960K views6 years ago FordTechMakuloco
Here we go! A little easy trans work to bring 4th gear back to your 4r70 transmission. These are the Parts and Tools I Recommend: ...
Wow, thank you for all this info! I can't address all your ideas, but I changed the cooling lines between the radiator and the little trans cooler radiator. And, last night I installed a new thermal bypass valve. I started the truck, and only the upper and lower lines got hot on the trans side of the valve, and then once warm, the upper line on the radiator side got hot, which means the valve worked and opened up to send the fluid to the front of the truck. I was able to feel the line getting warm that goes into the radiator, but then I didn't stick around to see if the lines got hot that leave the radiator and enter the trans cooler. I'll check it tonight! I'm hoping there's no clog. DO you know if the lines will feel hot by the time they return back to the bypass valve?
DO you know if the lines will feel hot by the time they return back to the bypass valve?
Use a point & shoot thermometer. Don't just touch cooling lines with your hands. If the return line is at or around your ambient temperature, with hot fluid in the cooling lines, you may have an issue. ATF in the return line is still hotter than ambient temperature. Just use your thermometer, follow the cooling lines, and you'll see the temps drop with consistency. The only way to fix a clog is by flushing out the lines and/or replacing them. You just replaced the bypass valve and confirmed that it works, and that fluid is returning from the valve back to the transmission. Since you know that hot ATF is flowing to the radiator, that means that there is no clog on the cooling side up to that point. You replace the line to the cooler, and the cooler. The only question would be if there is an obstruction from the cooler in the return line to the bypass valve.
I personally had a trans temp gauge added. I’d rather see the numbers early. Checking with your hand seems risky - if you burn yourself, will you be able to work?
I also have a Scangauge hooked up all the time, but mine doesn’t show trans temp. In any event, good luck with it.
I personally had a trans temp gauge added. I’d rather see the numbers early. Checking with your hand seems risky - if you burn yourself, will you be able to work?
I also have a Scangauge hooked up all the time, but mine doesn’t show trans temp. In any event, good luck with it.
You do know that you can code the ScanGauge II data for XGAUGE to report trans temp? At least, works on my '07.
You do know that you can code the ScanGauge II data for XGAUGE to report trans temp? At least, works on my '07.
Scangauge I.
And honestly, I prefer a traditional white-on-black gauge - easier to read, and safer than trying to concentrate on the tiny Scangauge screen while driving. But the Scangauge is great, too.
“Inspection port” or “test port” on top of the transmission. One poster said it was a black bolt. People have said both sides (drive/passenger) of the transmission.
I started an *ancient* thread titled “Transmission Temperature Gauge In A 4R75E Transmission?” But I don’t know how to link a thread.
Mark Kovalsky is a retired Ford auto trans engineer and has posted some useful info over the years, too.
The valve just got shipped and I’ll post an update soon.
FordTechMakuloco
