terrible popping noise

i just replaced the driver's side drive axle on my parents plymouth voyager van, but now after three days of the van running just fine a problem has started: a loud pop can be heard when turning the vehicle, it only pops once but i can feel it through the floor board. please help!

It's been a little since you posted this, so maybe it is solved, but I would check to make sure everything is fulling seated and properly greased. Also, are the joints still good, did you replace them? My experience with shafts and joints is that many times the universal/wobble joints (not sure what style is used) will pop loadly when wearing out, and usually with a lot of force. They only pop once though because then they have shifted into place and are tight. When you turn again, they have to shift into a different position, so it pops again.

Just my thoughts, could be something else, but it is a start point.

Honor

sound to me like a bad ball joint

sounds to me like a bad ball joint

I'd get the axle shaft replaced again. Not all axle shafts fit one application on Chrysler minivans. You might have gotten one for a different application. Their lengths are slightly different depending on engine/trans. combinations. And/or you have a bad rebuilt axle shaft.

Ah, heh. OK. I know this one by heart.
The popping you're hearing is probably the inner CV joint breaking.
Always, when you're replacing the left drive axle-replace the front motor mount as well.
What made the axle go bad in the first place is the fron motor mount gets sloppy and allows the engine to lean too far with the torque, allowing the axle shaft to come out of the transmission too far and run on an extreme angle-destroying the inner CV joint almost instantly.
Replacing the front mount is easy.
Put a floor jack under the bottom edge of the trans bellhousing to support the weight and unbolt the mount from the plate on the engine-then unbolt it from the front frame and bend the lock tangs straight and drive the rubber bushing (big square thing) out of it-it'll be a royal pain because it'll be rusty and spring loaded (it stays in because it works like a big tension pin).
Pound the new one in the same way and bend the lock tangs over and reinstall the mount. No more busted axle shafts.