Aussie 4 speed help

[Glenn 'Stinky' Stankevicius]

We have a few Aussie 4 speeds about, but I found one in our collection that has a sender installed just under the 3/4 shift lever.
It looks like a factory fit-up, can anyone shed some light?

[FCRB26]

Reverse lights ?

[FCRB26]

http://holdenpaedia.oldholden.com/Aussie_Four_Speed

[Glenn 'Stinky' Stankevicius]

Thanks Pete, I found the answer in that link -

The Transmission Control Switch only permits Vacuum Advance in Top Gear when the Engine Temperature is above 63 degrees C.

[Dr_Terry]

Thanks Pete, I found the answer in that link -

That is not quite correct. The switch on the gearbox side-plate simply tells the emission system that the gearbox is in fact in top gear (4th in a 4-sp or 3rd in a 3-sp). The 63 degree switching is operated by a separate temp which is mounted in the cylinder head directly into one of the many mounting, detecting the the temp. of the actual metal.

Dr Terry