I have a 5sp manual transmission. '97 4x4 150k mi. I've noticed that my back-up lights only work if the shifter is in just the right place, but...... If I'm in reverse, the reverse lights immediate and always come on as I begin to let out the clutch. Does that say anything about the condition of the transmission? Is that a bad sign of something about to go really wrong? Like the light comes on when it starts to torque up?

 

There is a backup lamp switch mounted on the side of the transmission, I would start by inspecting the wiring that connects to the switch.
and remove the switch, clean and test it and possibly replace the switch.
It should be just a simple normally open on/off switch.
What does it do with the, key on and engine off, when you put it in reverse and let the clutch out as if you were going to back up ?

 

I would guess the switch or the wiring, not the actual transmission. The torque is pulling on the wiring harness.

 

Sloppy shift linkage might do it as well.

 

Because wiggling the shifter left/right in its gate (reverse gear position) can affect lamp on/off, I'm voting for the sloppy shift linkage. Do others agree that can cause it? Can that be adjusted?