Rear end vibrating while moving slow - idle speeds

[toronado13]

I've taken my 2017 Expy in to the dealership and they tell me it's my tires, but I want a second opinion. I feel a vibration from the rear only when I let off the brake and start to move at idle speed, as I start to accelerate about 5 or so MPH I no longer feel it. Same thing as I slow to a stop in traffic and maybe let off the brake.

Tires are Wildpeak 285/70r17 on take off raptor wheels. Have had them for some time, and while they are a bit noisy, never had a vibration like this.

I've read up on a clutch going bad in the rear diff, but didn't know if this was a symptom.

Any thoughts on what to look for, or do you think it's the tires? I've poked around a bunch on them and they don't look like their damaged or obviously chunked. I just feel like the dealership took the easy way out in pointing out to me "these wheels and tires are not stock!"

 

[JamaicaJoe]

I would look at worn universal joints on drive shaft, rear CV axles. Sounds like they are worn and then re aligning themselves under centrifugal force.

 

[Trainmaster]

Swap the front and rear tires. That'll tell you if it's the tires. But my bet is with JamaicaJoe. I think it's universal joints or real axle CV joints.

You may also want to take a look at your parking brakes.