Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › replaced th400 know speedometer is off › Reply To: replaced th400 know speedometer is off December 27, 2020 at 3:05 pm #987809 Richard KirshyParticipant You could count the teeth to see if they match or not. If they do, it is possible the replacement transmission has different gearing than the original.