Electric Cart, stopped and will not pull

[JBS17]

While my wife and granddaughter were riding on paved street they explained the cart just stopped pulling. No reported unusual noise at the time. After reading several other post it sounded like the solenoid. Presently when I depress the excelerator it jumps about three times moving maybe a foot or so. Going to reverse produces the same problem. After reading other posts I raised the rear wheels off the ground and tried the same test. I found the wheels would turn when pushing the pedal but jumped erratically. Holding one side would somewhat smooth it out but just barely. The other side continued to turn but far from being smooth. I am now worried I have problems in my rear differential.
On the front of the cart it is identified as a "Prestige". I though it just had a body conversion but after finding the ID tag is appears to be a 2008 Rolling Golf Car. ???? Chinese made. Not what I thought I had bought ... but what I have.
Am I over worrying about the rear end and actually have an electrical problem? Anyone's thoughts?