Drive Train Question

I have a 89 K2500. It is making a Very loud clicking noise that I can't find. It sounds like it is coming from the Drive train. The only time you
hear it is when you press hard on the gas. It only lasts a few seconds, but it is loud enough to hear in a car follwing behind you. If you maintain a steady speed you can't hear it, unless you accelerate. I have checked the fluids in the Axles and Transfer case. I do have a bad U joint on the front of the Front drive shaft, next to the axle. My question is.... If you are in 2 wheel high, the front drive shaft is not turning correct? If thats the case.... the bad U joint shouldnt be the source of the noise.

Any help would be greatly appreciated
Thanks
Paul

This is just my opinion, so I ask that you not take it as gospel.

In a two wheel drive car, if I'm not mistaken, the differential will still turn the drive shaft even in nuetral when the transmission has disenagaed it. So, in theory, even though you transmission isnt engaging you front drive shaft, the differential in front is still spinning, and turning it.

Though, as I say, just my opinion, and theory at best.

the front shaft should NOT be turning. if it is, you have another problem. clicking that youre refering to does sound like a possible u-joint. i dont remember what year chevy went to IFS on that tk but if it has a straight front axle, you have u-joint at the front hubs as well that commonly go bad. make sure your front hubs are unlocking properly. nothing should be turning in that front drive line when in 2h except the tires.

i have been having the same problem with my 91 2WD 4.3. I have checked every thing and all is well. i did replace the motor mounts, but that only changed the sound a bit. Most people think it's a cracked flywheel. It's a place to start. If its good, when you hit with a wrench it will ring like a bell...if it's a dull sound, it's most likely a small crack in in the flywheel. Let me know if that works! I have the same problem.

Hmm..... true enough about the flywheel. Also, if the clicking is really loud (and maybe sounds more like someone hitting something) it could also be a torque converter. I had a Cutlass the made the loudest noise I ever heard. Several mechanics swore it was on its last leg, and that it was the loudest engine knock they had ever heard, but it turned out to be the torque converter had basically disintegrated.

And.... I do have to retract my previous statement, I forgot about the locking hubs and that whole mess, and ended up sounding something of a prat.

And.... I do have to retract my previous statement, I forgot about the locking hubs and that whole mess, and ended up sounding something of a prat.[/QUOTE]

Selphsirv

Don't apologize for trying to help , we just give our 2 cents right or wrong.

Peace

Found the problem... It was the Dust Cover out of adjustment. I had just put in the engine in a couple of weeks ago and must of not aligned it correctly. Sure am glad... I thought I was going to have to pull the engine again...

Whew!
Paul