Motor is thermally protected. At worse its controller shutting it down. I dont believe you can overheat the motor unless there is a mechanical issue.
Dragging brakes, bearing etc. Is differential noisy?
I drove my anvil wot 50 steady miles up and down hills. Speeds from 40-50mph and did not overheat motor.
Possible it has a shorted turn. Any industrial motor shop can ring it.
I sold 50 of those Kinetek motor for hotroding gems. We run them up to 9,000rpm 60 mph. No failures yet.
Iirc, Anvil motor is labeled 7.5kw and my motors 8kw. Same motor near as I can tell.
Before you ask, sold out 2 yrs ago. There still may be one or two on the shelf someplace. Price has doubled or trippled over my selling for $550 though.