You would need to get a trouble shooting manual to see if you can follow where the signal comes from.
On my 2000 400 the gear for the speedometer was on the left hand side on the transmission, but it was mechanical where yours is digital so there could be a sensor down there with some wires that could of been damaged.
You might be able to look at a parts diagram from a online parts source and see if you can tell where the signal comes from.