74 Electronic OD suddently not working

I've had my car for many years and am aware of the jerking sensation when the OD is low on oil. I just took it out as I plan an 1100 mile drive next week from CA to OR and want to shake it out first. I do not detect my OD at all in either 3rd or 4th. Just nothing there. I have never had this happen during my 17 years of driving it. I suspect an electrical glitch. My long time MG mechanic passed unexpectedly last year or I would call him and ask "what gives"? Any suggestion on what to check out will be greatly appreciated.

I've had my car for many years and am aware of the jerking sensation when the OD is low on oil. I just took it out as I plan an 1100 mile drive next week from CA to OR and want to shake it out first. I do not detect my OD at all in either 3rd or 4th. Just nothing there. I have never had this happen during my 17 years of driving it. I suspect an electrical glitch. My long time MG mechanic passed unexpectedly last year or I would call him and ask "what gives"? Any suggestion on what to check out will be greatly appreciated.
When was the OD unit serviced last? Hope it wasn't 17 years ago! If it has oil in it, then it could be a defective OD switch, a broken wire, or possibly a dirty solenoid in the OD unit. I'm sure you would know if it was a internal gear problem.

Thanks Paul.