lost all my transmission fluid from underneath my 2007 volvo S60R with the TF-80SC auto transmission from the front driver side, any suggestions what could've caused this

 

My most likely guess is a transmission cooler line or the cooler itself (part of the radiator). Did you run over something recently that could have damaged the underside?

 

Nothing that day that scraped the under pan, I did take the dust cover off the bottom and saw transmission fluid running all the way down the driveshaft so I’m starting to believe it’s the driveshaft seal

 

On a AWD car - If so - that's not transmission fluid, that fluid would be coming from your angle drive (which is a thicker, smelly 90wt or so HP (high pressure) lubricant - like a differential fluid)

 

anyway to surefire check if its the angle gear fluid or transmission fluid or will i have to drain and guess
?

 

surefire way is to find the source of the leak :-) you can try putting some white paper under the car to see if you can tell what color the fluid is. Transmission fluid is reddish brown (or brownish black ugh) gear oil is usually golden/brown. You can also check the level on the transmission using the dipstick (some are hard to find as they can be way down near the bottom of the driver's side of the radiator). Not sure about the bevel gear but if its like most MTs or rear differentials there's a side fill plug that you can stick a pinky into and you should feel some fluid.

 

Pop the pipe off the air box (outside air from bumper to airbox) and reach down near the lower coolant hose for a yellow dipstick for your transmission fluid and check that like mt6127 said. It has a clip on it (part of the tube) that you need to move away before you can remove the dipstick.

 

Check the cooler lines that go into the radiator. On the side of the radiator. My V70 blew off one of those lines and hemmoraged all of the ATF. There is a locking clip that can fail, causing the line to blow off the radiator. Make sure to top off the ATF and be sure the line is secure before starting or it will spit out all you dumped in.