Transmission fluid leak

[DavidL]

I have a slow leak from the transmission on my 1999 Taurus. When I look from below, I can see wires going to some type of sensor on top of the transmission, and it looks like the leak is coming from somewhere in that area. I can't get a direct view of it from below or above. Is it likely the leak is coming from the point where the sensor is mounted in the transmission? It looks like it would be a booger to get to.

[drdisque]

it's unlikely, but possible. That is the Vehicle Speed Sensor.

[shorod]

If he's looking at the VSS, I have seen leaks from them before. I'm not sure on the 1999, but previous years have used an o-ring seal to keep leaks from happening, but the seals can get brittle and leak.

I've not see Transmission Range Sensors leak (if that's what DavidL is looking at) but I suppose it's just as possible for that to leak as the VSS.

-Rod

[zorobabel]

Originally Posted by DavidL

I have a slow leak from the transmission on my 1999 Taurus. When I look from below, I can see wires going to some type of sensor on top of the transmission, and it looks like the leak is coming from somewhere in that area. I can't get a direct view of it from below or above. Is it likely the leak is coming from the point where the sensor is mounted in the transmission? It looks like it would be a booger to get to.

I'm almost in the same boat as you are with my 99 Duratec wagon. The difference is that the whole left side of the engine is covered in transmission fluid, and I have no idea where the leak comes from. After one longer trip, over 1000 miles, it was leaking really bad, I had to put 1 quart of Mercon V back in. Now it's leaking "normally" again. I hope you discover the origin of the leak, so I'll have a starting point

[tripletdaddy]

To locate you leaks, you really need to mop those things off with some rags and possibly some other automotive cleaner. DON'T use a pressure washer. The main thing is getting it good and dry. Possibly an engine cleaner or brake parts cleaner can be used with caution. Either take it for a drive, or possibly you could just idle it in place. Maybe shift through the gears, but don't move it and look for leaks. A newspaper or cardboard under it for the idling or overnight park will help pinpoint your leak. Sometimes something might need a little tightening or the gasket is shot.

[shorod]

I've had good luck with installing dye in the system, then using a UV light to detect the source of the dye. The dye kits are getting pretty easy to find in stores and are not all that pricey. It does help to start with a clean surface though to really pinpoint the leak source.

-Rod

[rdh2]

I have also seen leaks at the transmission wiring harness connector on top of the trans next to the side pan. To replace that connector and harness would require removal of the trans side pan.

[mwt47]

It could also be a blocked vent tube.

Fluid would come out of the dipstick then

Mike