my 1999 Corvette c5 convertible has gearbox problems.its a four speed automatic i had a gearbox specialist look at it and they said the gearbox oil was low and burnt smelling.they topped the oil up and drove it for 3 miles it had no drive in 3rd gear only slight drive in 4th with more than full throttle. They said they couldn’t fix it as they don’t have spares for American cars. Can anyone recommend a gearbox repair garage that can help me.i based in the Newcastle northeast of England. Any help would be much appreciated.