loud snap in front diff, no more 4x4
 

i was doing a truck pull with the dodge, i pulled about 6 times with no issues. the last time i pulled i was starting to loose so i lit up the tires and the truck was hoping a bit and i was on and off the throttle and all of the sudden i hear a loud snap. everyone tells me it sounds like it came from the passenger side front axle. no obvious u-joint failure, so i drive it forward and it drives fine. go to turn it and its definitely not in 4x4, and the 4x4 light wont come on. otherwise it drives down the road just as good as it always has. im thinking problems with the central axle disconnect? i know a loss of vacuum causes failure to engage or stay in 4x4 on these trucks but it it common to disengage with a bang like that? i figure the axle was so loaded up that if the axle did disconnect it would kind of have to do so with a bang. whats your guys take on it? if i had a broken axle shaft wouldnt the 4x4 light still be coming on?

Probably twisted the splines of the intermediate axle shaft up there. My buddies truck had that happen. His vacuum system was not working and he kept pissing around with it until finally he messed up the splines on it. Problem being, it was only engaging the axle shaft by about 1/4 inch, not near enough to handle the load. I guess, what I'd do is take the axle shifter off and see what's broke in there....

I think you're right with the CAD. Either split the sliding collar, broke the fork or, as stated above, twisted the splines of the intermediate shaft. This is where a lot of people buy a one=piece shaft and ditch the CAD.

the central axle disconect is all fine, and i notcied the 4x4 light still works fine as well. when i had the CAD removed i slid the collar over and locked the front end manually and spun the front wheel and the opposite wheel didnt respond like it should have, being that its an open carrier the other side should have started spinning in the opposite direction, it did absolutely nothing. both sides spin freely whether the collar is engaged or disengaged, no difference. i also noticed i can only turn the pinion a little bit in either direction and then it stops and wont turn anymore. when i put the truck in 4x4 and drive it the drive shaft turns fine and makes no noise, but i cant turn it with my hands with the truck up in the air, something is bound up yet no funny noises come from the front end. i put the truck in 4 low in 1st gear and got out and walked beside the truck as it idled forward and got up close to the front end and cant hear anything making any noise. next time i drive the truck ill put it in 4x4 and kill it and coast without that noisy cummins running and see if i can hear anything.

the diff fluid is really dark, thick, and sludgy and i just changed it about 2 months ago. i need to pull the diff cover but i really cant afford to buy fluid at this point(i know im a dumb ass, truck pulling with no money). am i safe to be driving this thing around or should i be concerned with further damaging the front end?

You'll be fine driving it.

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Put it in 4wd and see if you can turn the driveshaft by hand.

I'm guessing that's the result of all the little iron pieces you prob have floating around in there. If it were mine, I wouldn't drive it. With the CAD being ok, my next guess is you wiped the teeth off the pinion gear. The more you drive it, the more those little pieces/parts get pushed through the bearings, spiders and carrier. Chances are it's gonna be an expensive fix no matter what. Not much sense in adding to the bill but that's just my opinion.

i pulled the cover today, everything was fine, spider gears were good, ring and pinion were not missing any teath. the axle shaft on the driver side is broken, my aftermarket outer axle seal just supports it well enough that its not not noticable, its not like its flopping around in there. the wheel spins free and the spider gear doesnt, nor does the axle shaft(its not the splines). however the pinion is difficult to turn and i cant tell why, it tuens about a quarter turn and stops, the ring and pinion turn free throughout this 1/4 turn then all of the sudden you have to muscle it to do a half turn, then 1/4" of free spin then muscle it again to get a half turn. all the bearings seem clean since they are isolated from the axle tube since the stock oil seal at the pumkin is still in place. im thinking maybe its just the u-joint? the joint looks like a spicer joint so im sure its original, nobody ever replaces anything with quality componants.

i guess ill pull the front drive shaft tomorrow. i shouldnt have even wasted the fluid on the front diff until i get things fixed, nothing is spinning in there anymore... im probably getting better mpg lol.