Anyone had any success/failure with lemon law?

2019 GMC 3500HD DRW Denali. Purchased in 4/19 and traded in my 2017 Chevrolet 3500HD DRW.

Truck has been in the shop a ton. Shot rear end at 1600 miles. Was determined that it left the factory with no gear oil. Second rear end failed 2 weeks later....they tried to re-use some of the parts from the old rear end. After that, it appears the rear end is OK.

However, the truck has had a vibration every since. I don't recall if it had it before because I just had the truck so off an on while they were trying to figure out the rear end. The vibration is only under a load going up hills or during acceleration.

It has has had 4 sets of tires, 2 driveshafts, new axles again, toqrue converted changed and they still have no clue what is causing it. This time it has been in the shop for three weeks and they are taking guidance from GM Tech Support which is now at a loss as to what the issue is.

They have run a Pico Scope on it but GM says it is not picking up enough to tell them what it is. The dealer has begged GM to come down for a ride along and are on my side. They feel and hear the vibration as well. They and I have also driven three other identical (other than color) trucks on their lot that do not do this.

I have everything in emails so I have documentation showing the dealership admits they have no idea what to do and that the problem does exist on only my truck.

At this point, I have been using the "catch more flies with honey" approach. But, this is getting old.

Sounds like they did not shim or torque the pinion correctly. I had 99K on my 2011 F150 and I let the service guys talk me into a drain and replace the differential oil as part of the service. Bad mistake, I should have referred to the if it aint broke don't fix it policy. So a month after the new differential oil, awful noise from the rear. Take it in, "Well the clutch pak needs replaced". So $1100 for a clutch pak replace. Then 1 month later, really awful noise from the rear again. This time "Well, the pinion is shot". That is when I found how critical it is in shimming and torquing the pinion assembly. I made them eat it and refused to pay for their screw up. I firmly believe that there are no good Rear differential mechanics in the world. This is why you are still having problems. The only way to fix your GMC is to have them put a brand new factory setup Rear in it. Believe me. It will never be right.