Bad differential??

I've got a '99 Pete 379. About 3 weeks ago I got loaded at one if my usual customers. I usually haul a little heavy 92k+. There's a steep short driveway to climb to get to street level. When I'm backed into the dock my trailer is flat but the tractor is already headed up the driveway.
I've been there 1000 times, but this time I started spinning a wheel then heard a loud snap. I backed up as much as I could , timed traffic so I didn't have to stop on the hill and put my foot in it and made it out with no issues.
Truck developed a bounce. If I was on the low side of the rpm's for the gear I was in (1200-1300) it would bounce until accelerated or shifted.
Bobtailing one day i turned down a street (90 degree turn) and i though i was going to get bounced out of my seat. It stopped when i was straight.

Then I was pulling a flatbed ( something I don't normally do) I strapped down the totes I had on, but being 5'8" and 135lbs I can pretty much hang off the winch bar and not move it. So once I left I was paying more attention to my trailer than normal because I didn't trust my strapping job. That's when I noticed the nose of the trailer walking around a lot. The next day I had my reefer back on and was headed home empty and it was bouncing a lot. If I accelerated when it was bouncing, the bouncing stopped. If I accelerated when it was fine then it would start bouncing.
Got home had mechanic pull front axles. They were not broken.
Rear diff had no metal
Front diff had miniscule pieces of metal.
Found center pin on left front springs was broken and U bolt was loose. Axles were out of alignment by about 2".
Hoping for a miracle we replaced center pin, tightened u bolts and realigned . Axles are out less than 1/4" now. Took it for a ride tonight with empty trailer. Symptoms are all still there. The bouncing, trailer moving and it's harder to handle a little bit. Seems like I'm having to move the steering wheel back and forth more but maybe that's from the trailer moving.
There is no grinding or clunking noises but I'm still going with a bad differential.
Bobtailing is easier but that's it for improvement before it acted like the inter axle lock was in. But I haven't used that in months.
I know a bad diff can cause a vibration but I haven't noticed that only the bouncing.
So before I tear this down I thought I'd reach out and see if anyone had any other ideas or things I should look at while it's apart.

 

Ok I had not thought of that. This truck has had a lot of drive line issues. I took all drive shafts out and had them balanced altogether. Haven't had any problems since so I was not thinking about that at all. That's easy enough to check. Thanks

 

This could be a very real possibility. With all the driveline issues I've had that has been mentioned before. I watched a video from Peterbilt that shows how to check ride height. It shows to run all the air out of the system. My mechanic did not do that. I showed the video to my mechanic and he told me it didn't matter. He did adjust it a bit. However, I think I should take it to Peterbilt and have them do it. I'm pretty sure it does matter.