High Trans Temp Alarm

[smitty]

I have a 2007 28TE. This past weekend I had a high trans temp alarm go off. I checked the transmission and it was cool. Now as soon as I turn on ignition with the engine cold, the alarm goes off. Any ideas? Thanks for any feedback.

[rebuckley]

A few thoughts - I assume this was also tested from a cold start? SO you know the oil was cool? (1) sender could be bad - they work through resistance usually - so you can use a multi-meter to see if it simply jumps to the "open" (or "closed" I always forget which) to cause the alarm. (2) If it wasn't fully cool, maybe the transmission oil pump has failed? So the oil is not being sent to the cooler anymore?
I would try the simplest fix first, assume sender or sender wiring is bad.
<EDIT> I see you said cold start - so I would go with the sender being bad (or wiring to sender) it sounds like once you give it voltage, it completes the circuit and sets off buzzer

[smitty]

The alarm goes off when i turn the key, I dont have to start the engine. One problem is I can’t find the sensor on tranny or heat exchanger. This boat has the yanmar 6lp 315 hp engine with a zf 63a transmission.

[RobS]

Very confusing that you started two different threads on this ????? ........ I replied to this earlier:

viewtopic.php?f=5&t=11207