Transmission + Cooling system questions | Ford Explorer - Ford Ranger Forums - Serious Explorations
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February 20, 2022
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City, State
Milford, NH
Year, Model & Trim Level
2008 Mercury Mountaineer
Hi everyone!
I have a 2008 Mercury Mountaineer Premier AWD that has been ran hard by previous owners. It has leaks from the trans cooler lines, and the fittings on the radiator. I had planned on replacing the fittings, but after I removed the trans lines, and drained the trans fluid from the radiator, overnight all of my coolant drained out of my radiator from the trans line fitting (weird that that happened overnight, and when I drained the trans fluid the day before it wasn’t mixed with coolant at all). I decided to replace my radiator, and trans cooler lines (from transmission to radiator, and from radiator to aux trans cooler), and decided to also do new hoses, thermostat housing, and thermostat while I was doing the rest of the cooling system. The transmission fluid is presumably low as the leak was getting a little worse and was going on for a while. I’m also doing a transmission service as I don’t want the old trans fluid in the new lines or radiator. I have a sealed transmission, and bought a weed sprayer to fill with fluid to spray into the transmission. Will this work to completely fill my system? Or will I need a pump and to pump in through the cooler line to refill the trans lines, radiator, and aux trans cooler? I should have everything completed within a few hours and need to know what my next step will be. Fingers crossed everything goes well, every time I try to fix one thing on this car, I find 5 other things that need to be done as well. Next weekend will be my rocker panels.
 






07EddyB

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Bowling Green, KY
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2007 Ford Explorer 4.6 V8
It's certainly weird that your coolant drained out while the trans lines were unhooked. It should be a separate component in the radiator to avoid mixing fluids. Did you by chance loosen the transmission line fittings at the radiator? That's the only way I can think of that might have loosened a seal internal to the radiator between the two.
In terms of getting fluid back in the transmission I assume you have the V8 and thus the 6R60. There is a 'stick' on the passenger side that will allow you to put fluid in. Hard to describe - just do a search on it. My weapon of choice on this is just a simple fluid pump - this one:

Mityvac MV7241 Fluid Transfer Pump​

It's a tight fit so I set mine up to use some 1/4 inch copper - like you would use for an ice maker line. It allows me to hook it over and doesn't collapse the flexible line that comes with the pump. Be warned - it's a PIA to deal with. It's extremely awkward and it's right next to the convertor - and you have to check it when it's hot. So at least wear a long sleeve shirt.
 






Joined
February 20, 2022
Messages
2
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0
City, State
Milford, NH
Year, Model & Trim Level
2008 Mercury Mountaineer
It's certainly weird that your coolant drained out while the trans lines were unhooked. It should be a separate component in the radiator to avoid mixing fluids. Did you by chance loosen the transmission line fittings at the radiator? That's the only way I can think of that might have loosened a seal internal to the radiator between the two.
In terms of getting fluid back in the transmission I assume you have the V8 and thus the 6R60. There is a 'stick' on the passenger side that will allow you to put fluid in. Hard to describe - just do a search on it. My weapon of choice on this is just a simple fluid pump - this one:

Mityvac MV7241 Fluid Transfer Pump​

It's a tight fit so I set mine up to use some 1/4 inch copper - like you would use for an ice maker line. It allows me to hook it over and doesn't collapse the flexible line that comes with the pump. Be warned - it's a PIA to deal with. It's extremely awkward and it's right next to the convertor - and you have to check it when it's hot. So at least wear a long sleeve shirt.
I have the 4.0 v6. I have everything back together. I replaced my trans cooler lines from transmission to radiator and from radiator to aux trans cooler. I replaced my radiator, and while I was doing that got a new thermostat and housing, and new radiator hoses as well. I plan on using a weed sprayer to fill the transmission through the drain plug/tube on the bottom of the transmission. Will this circulate the fluid into the trans cooler and the radiator while the vehicle is running since the trans cooler was drained when the line was pulled and it’s a new radiator?

And yes I did actually completely remove those fittings with plans to replace them because I had leaks from them. I bought the new brass fittings and the disconnect tool, but the lines just would not separate so I removed both the fittings and left them attached to the trans cooler lines, and replaced those lines as well. Oh well, I guess I should have a reliable cooling system now.
 






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