My tow rig is a 1997 F350 Powerstroke. Only modifications are cold air intake and 3'' downpipe to straight piped with 5'' outlet. When I am pushing the truck up a hill or anytime when the motor is under a load I hear a "clicking" sound coming from the rear/center of the motor right behind the dash.
It sounds like an exhaust leak to me but when I inspect I do not see any cracks, loose clamps, or areas where exhaust residue is obvious. Any suggestions?

It could still be a leak...It could be very small that you can't see it with all the junk under the hood of a 7.3! Keep your eyes peeled.

I know i am talking about a different brand of diesel and quite a few yrs difference but i had a noise similar to this in one of my Duramax's that got louder over time and it turned out to be a blown head gasket.

It sounds like the tubes that connect the exhaust manifolds to the turbo or maybe that exhaust valve under the turbo that restricts the exhaust to warm the engine up faster.

You might check the turbo , the four 12pt. flange bolts are prone to back out.

just my 2 cents, but i had a 94 with the turbo diesel and i had a similar noise. it was actually the fire wall cracked right above the exhaust tube going down from the turbo charger. the crack would rub on itself when i got on it. i pulled the exhaust off and reached up in there with a wire welder. stopped the noise.

It sounds like the tubes that connect the exhaust manifolds to the turbo or maybe that exhaust valve under the turbo that restricts the exhaust to warm the engine up faster.

That's what I was thinking as well, based on the location of the noise.

Thanks for the input guys. I will check out these options and see what I find!