we do break alot of parts. my old d44 you could pull the axle u-joints out without a hammer. thats why most of the people who do rock crawling jump to massive axles so we dont break as much. but i have still seen little bitty tj's with d60 fronts snap them like pretzels because of binding when a d60 on the front of a little tj breaks it's funny as hell cause the whole rig jumps.

 

I've read a few of these posts trying to find out if there is something I could do to make the jerking less, and I've noticed that no one even knows why it does it. Here's part of the answer:
It seems to be worse on posi-traction ....... When turning a corner the rear wheels are pushing straight ahead - the two front wheels are turning (or going around) at different speeds from each other and from the rear wheels. When turning a tight radius the inside wheel has to make less rpm's than the outside wheel ........ and both front wheels are turning at different rpm's than the rear wheels. The positraction is trying to make up for this.
None of that is AS noticeable (but still noticeable) in snow because the inside radius wheel is sliding in the snow.
Back in the 70's I had a 4X4 with this problem with a new truck I ordered and I ordered it without positraction. At the factory they put positraction in it when it was built and when it got to the end of the line and fluids were added they put the wrong fluid in the differential because it was supposed to be non- posi differential. The mechanic (who was just back from factory trained schooling where he learned the following procedure) drained the differential put something in it called fish oil, ran it for, I think it was, 1000 miles. He then drained the fish oil and put the right fluid in the diff.
He said the positraction has little "clutches" in it that get gunked up with the wrong fluid and need to be cleaned (with the fish oil) and the proper fluid must be used...... Now I'd like to try this on my 2001 Dodge diesel pick up but I'm wondering if there is anything (in the last 40 years) new to try.
This must be a well guarded secret because I don't think I've ever run into anyone who heard of this. How about anyone out there?
Isn't it amazing that in 40 years people are still having the same problem I had back in the mid 70's.

 

You're right, it jerks because of the wheels turning at slightly different speeds. When I was in the Marine Corps, HMMWVs do it really bad because all 4 wheels are powered at all times and are all locked. I'm surprised that they don't break more often.