Was out wheeling with my friend. He was in a SAS 80's pickup when his front axle failed. Limped it home thinking it was an axle shaft. After we got it apart it turned out to be one of the adjusting nuts on the Third member had been pushed with enough force to push it right through the threads. Broke the outer race on the bearing as well. Gears were in fair shape still. Just curious what could have caused that much force to push it out like that. It was welded and the plate had come loose and gotten chewed up. My thought is that the plate/ debris got caught in the gears maybe? Hard to believe that could have happened and the gears are all fine though.

Just curious if anyone else has experienced this or other theories. Fortunately he had a parts truck so he just stole the Third out of it for a fix....

 

By adjusting nuts you mean the big rings right? And by welded plate do you mean like the filler plate when you weld spider gears?

those adjuster rings can get destroyed if you don’t put enough preload on them and can be made worse by not using the locking tabs properly. The rings require quite a bit of preload. It’s a lot of side load pressure being applied to the ring from the pinion, especially in 4 low in a crawling situation.

 

Yes and yes. Not sure about the preload. Axle was what it is when he bought it.

 

yea whoever set up the gears probably didn’t put enough carrier bearing preload mixed with pieces getting wedged in the teeth. Bummer. I don’t remember what the torque spec is for those adjusters but I remember it being kind of a lot.

just checked my notes, those require 120ft lb. Tell your buddy to use gearinstalls.com for notes if he’s gonna get a new 3rd and set them up himself. Also yotamasters will sell master diff set up kits for a good price.