Help! - FJ40 speedometer sender dilemna (1 Viewer)

[Maintz]

I'm replacing the speedometer torpedo (sender) in the tail section of my transfer case with an AutoMeter sender. The threads on the torpedo are the same as the AutoMeter (GM) sender,.. a bit of a surprise - thought they would be metric!

So, my question is: Will I need a Toyota speedo gear or could I use a GM gear,... are they, infact, interchangeable?

Thanks for any help.
Maintz