1997 6BTA 5.9 w/ ZF Hurth

I have a 1997 Maxum 4600 SCB with two Cummins Diesels. Trying to locate the RPM sensor. Don’t know if it was placed on the alternator or the transmission. Do not know what it looks like. Been all through the internet and pictures. But cannot find just a flat out picture or drawing or comment that says it right here. We bought a Livorsi DC4000DA to replace the old gauge and I know mean that means Alternator driven. They are pegging past the 4000 limit on an engine that should only max out at 3000 rpms. Tried the adjusting screw and it’s just not changing the reading all that much. After reading some info from this website alone I think we have the wrong one. But still need to know exactly where I should be looking for the sender itself and what it would look like. Thank you.