Question about the rear chassis harness

[House Money]

I'm using an LS3/4L75E. In routing the rear chassis harness I notice a pair of speed sensor wires splitting out about 3' from the forward end of this harness. Do I need this connection? I'm thinking not but would like to confirm.

Thanks, Gary

[Pat Landymore]

I’m fairly certain it depends upon what feed your speedometer is taking.

If you’re using the FFR supplied speedo with no other computational power in between, then likely you’ll need it.

If your feeding it directly from your LS3 PCM, almost certainly you won’t.

[House Money]

Thanks Pat. I should have mentioned in my post that I have the Speedhut cluster.

Gary

[edwardb]

Speedhut GPS gauges don't require a signal from the transmission speed sensor (TSS) which is what those wires in the Ron Francis harness is for. So no on that front. Your LS3/4L75E combination may require that signal however. Depends on your setup, controllers, etc. I'm doing a truck build also with an LS3 but a 4L65E transmission. The Chevrolet Performance crate engine control pack I'm using does not require a TSS signal. However, the HGM transmission controller I'm using does. At this point, I don't know whether I'll use the Ron Francis wires or the harness that came with my HGM controller. Hope to know if a few weeks after my kit is delivered and start mocking things up. I already have the engine and trans and related electroncis.

[House Money]

I dug out the transmission harness and i see that it has a speed sensor connector that fits my trans, I have removed the sensor wires from the chassis harness.

Gary