After my two week, 4400 mile vacation trip into the mountains of Colorado, I came home to find that there seems to be a leak coming from the transmission. I've had the transmission rebuilt just over two years ago, and haven't had any issues since. I put a plastic container under than tranny overnight and this morning I found a small puddle of yellowish fluid. It's oily, and after whiping my fingers of with a towel, they felt sticky... Pretty sure its ATF. I jacked up the car, and got underneath to inspect. The leak seems to be originating on the top left (driver's side) and then run down. I was unable to see exactly where it starts looking from the bottom, or the top. Too many things in the way. What could be up there that would leak?
Thanks!

 

Tranny fluid is red.

Brake fluid is clear to amber and oily in texture.

Your brake master cylinder is in the vicinity you are describing.

At least it's easy to check.

 

O'rings could be bad too . I had to replace them all because of minor leak on my Jag , I feared the worst but glad that was a simple fix

 

It could be coolant leaking from one of the hose connectors.
Your description sounds like what I had. I changed the o-ring in the Norma connector and it was fixed.

 

Left a clear plastic bin cover under the car over night. Here is what I got:



Plums suggested it could be brake fluid, so I opened the brake fluid tank and took a "sample" (circled in red). The leak I'm getting from the trany area is circled in green. And like I said, it looks to be originating in the top left side (circled in green on the next pic):



Could it be coming out of the breather (in red circle)?
With the tranny in the car its pretty much impossible to see, or even reach the breather area, so I have no sure way of confirming this.

Thanks.

 

That fluid looks orange to me. I was just under my car with the coolant system pressurized and was getting fluid dripping from exactly the same spot. It would run down the side of the bell housing and drip off the transmission pan flange. The heater hose (octupus hose) lays across the top of the transmission directly behind that yellow plug on top of that top rib. I never could identify a stream under pressure from above because the hose appears to have rubbed along the bottom. I'm trying to confirm the part number now. At first glance I thought I had coolant leaking out of the transmission.
The hose is a bear, but definitely easier and cheaper than transmission work. Worth fishing your hand down in under the throttle body and checking.

 

Why don't you check to see if the leaking fluid is water soluble. If it is, then it is either coolant or brake fluid. If NOT, then it is transmission fluid or engine oil.