Vibration from Rear Axle

[DomMegacab1500]

i Hi Guys,
at First sorry for my English im from Germany i hope i can explain my Problem.
My Truck is a 2006 5.7 Mega Cab with the 8 Bolt axle probably the 11.5 GM Differential. RWD only !
My issue is that when i accelerate from stopping an make directly left or rigth turns the truck is vibrating but only for a few seconds when the truck is rolling it dissapears it is worster when i tow my camper it has only 1.6 tons.
I already canged the Wheel Bearings Rear and the U joints comlete and the middle bearing of the drive shaft. Also i changed the oil and a dealer here said its recommendet a Limited Slip Additive so i put 240 ml of mopar LS Additive inside with the oil 75W 90 GL5 before another Dealer filled in 75w 140 LS so im confused now what is the right oil and is LS Additive neccesary ??
The Truck drives on the German Autobahn smooth i love it but the turns from Stopping is horrible also when i back up in the Parking space it is a Vibration.
I Hope someone here can help me to fix the Vibration.
THX in advance

 

[DeckArtist]

Sounds like a brake issue rather than a rear axle issue. Was going to say U-joints but you already changed them.

 

[DomMegacab1500]

The Brakes i checked it is all good, already changed the Brake fluid and there is all good in Germany you have to go every 2 jears to the tüv its a tecnical inspection and they drive the truck throu a Brake tester so you can see how much force it has and that it opens again there was also all good. and my Truck has no traction controlsystem

 

[Zoe Saldana]

How did you identify it is coming from the rear?

i Hi Guys,
at First sorry for my English im from Germany i hope i can explain my Problem.
My Truck is a 2006 5.7 Mega Cab with the 8 Bolt axle probably the 11.5 GM Differential. RWD only !
My issue is that when i accelerate from stopping an make directly left or rigth turns the truck is vibrating but only for a few seconds when the truck is rolling it dissapears it is worster when i tow my camper it has only 1.6 tons.
I already canged the Wheel Bearings Rear and the U joints comlete and the middle bearing of the drive shaft. Also i changed the oil and a dealer here said its recommendet a Limited Slip Additive so i put 240 ml of mopar LS Additive inside with the oil 75W 90 GL5 before another Dealer filled in 75w 140 LS so im confused now what is the right oil and is LS Additive neccesary ??
The Truck drives on the German Autobahn smooth i love it but the turns from Stopping is horrible also when i back up in the Parking space it is a Vibration.
I Hope someone here can help me to fix the Vibration.
THX in advance

 

[DomMegacab1500]

It feels like and the Frontaxle is all new, wheels are Balanced, the vibration is when i drive forward or reverse so it can not be the Transmission, the ujoints complete are new, the transmission mount is new, motor mounts are good, tires are about 80%, rear wheelbearings new also in the front, and when i acelerate from stopping strait there is no vibration.