i have a 99 dodge ram 1500 4wd and on my way to work this morning this really loud bang would start banging and i was like whats that and i stopped looked couldnt find anything and i put it in 4wd just to see what would happen and it went away and i put it back in 2wd and it started and when i turn left it goes away i think its something to do with the 4wd drive shaft but any ideas?????

 

check u-joins

 

Set the parking brake and block the tires, then shift the transfer case into neutral; crawl underneath and forcefully yank the rear driveshaft this way and that. If it moves, you probably have a broken snap ring on the tailshaft of the transfer case. And you'd do very well to not drive it another foot until it's fixed.

Pictures of what can happen: https://dodgeforum.com/forum/2194754-post1.html

The best fix: http://www.drivetrain.com/parts_cata...ase_saver.html

If it's a broken snap ring and it hasn't already cracked the transfer case, then the good news is that it's a cheap and easy fix.

 

I once broke the ring gear in the diff on a 2WD car, which would make a horrible clunk clunk clunk when turning left (or right) only. It was fine in a straight line. Just a thought, since you mentioned the noise changed when turning.

 

does that sound like the drive shaft in the front?

 

Lotsa metal under there to transmit sound every which way...... if you can get it to do it at low speeds, walk beside the truck, while someone else drives it slowly, and turns things.... large parking lot would be a good place for this exercise.

 

it has to be something with the transfercase or drive line cuase it will stop in 4wd would it be the snap ring or u joint or something along those lines i need to get it fixed asap

 

front axle u-joints or wheel bearings.
to check axle joints, reach under the truck and grab the inner axle, rotate it back and forth and look/listen for play at the joint. should be none.

to check wheel bearings, grab the top of the tire and rock it in/out with all your might. should be no play.

 

Clicking is common when unit wheel bearings die..

 

i would check u joint or just try to turn each drive shaft and check for play. also i agree on checking your tranfercase in neutral