Hello! I have a coolant leak that I cannot find where it is coming from. It seams to be dripping from above the transmission bell housing. The weird thing is, is that it will only leak when I am driving. Not before, not after. I can idle in the driveway I 20 minutes and still no leak until I start driving. Also for the amount that is on the drive shaft. There is not much evidence up above of that level of coolant leak. Any suggestions on how to find it?

 

That's a cool leak, but I'm not sure it's the coolest leak!

Right above the bell housing is the "water bypass outlet." http://web.archive.org/web/201208130...68cylinder.pdf That connects the coolant system to the lower intake manifold, and the block itself holds the sensors critical to your trucks operation (ECT sensor, CSI Timer, TVV, 4wd A/C sensor, and the sensor for your water temp gauge). I'm going to bet the gasket between the block and the lower manifold has let go.

It will only leak when the engine is running, because that's the only time the coolant is pressurized. In theory, you could squeeze a mirror back there (there is very little room). But you might be able to do the trick with a paper towel. Get it completely dry and grease free, then start the engine. Carefully slip a towel in, and see how far down the water wets the towel.

Good luck!

 

Your heater core box has a drain tube that goes thru the firewall in that aera also.
If the carpet is wet at all on the passenger side that might be it.