Tapping-Knocking noise in driveline engine area 2007 Yukon Denali 6.2

[62gto]

I have a noise that I can’t seem to pinpoint. Under acceleration there is a tapping- knocking noise that seems to be coming from the front of the truck. I recently replaced the engine with a GM Goodwrench reman. It has new front wheel bearings, axle shafts, motor mounts front differential mounts and carrier side bearings, water pump, idler pull-ups, belts and belt tensioners. This fricking thing is driving me nuts. It won’t make the noise in park while free revving the engine, or while brake torquing the engine. It only happens when driving down the road. Oh, and did I mention that the noise was there before all those parts were replaced?

[CamGTP]

Did you re-use all of your exhaust parts on this new engine?

 

You could have a cracked exhaust manifold or a leak on the manifold to the y-pipe. I see leaks at those when the engine is in gear and under load.

[Ian Mills]

Have you ruled out u-joints?

[Mike GMC]

Yeah, I was thinking front drive shaft, or axle end joints as well.