[TR] Overdrive Quirk

[George Haynes]

 Strange new problem with the overdrive in my TR4A.  When the engine's cool,
it works fine.  When warmed up - maybe 10-15 minutes - it has a tendency to
drop out while the OD relay inside the car chatters noisily.  It goes in and
out of overdrive at will.  I bought a new relay and experience the same
problem but it takes longer to happen and remains in OD for longer periods,
but eventually drops out by itself.  Same relay chatter.

I thought I could use a relay from Radio Shack but cannot seem to make it work
at; it is intended to switch higher current, as in high-wattage headlights or
horns. I'll try that again, anyway.

The gearbox is filled with oil.  Could I have two bad relays?  What am I
missing?

Thanks!
George