Susan,
What Haynes is refering to and how it relates to your situation is dependent upon whether you hve a manual transmission or automatic transmission.

If an automatic trans, the Haynes "warning" does not apply.

If a manual trans, the only time you would have to worry is IF someone has rewired the OD controls to bypass the 4th gear switch AND the dash light is on when you shift into reverse AND then drive backwards AND go over about 10 mph in reverse.

I hope you resoldered the relay in an automatic trans vehicle. Doing so in a manual trans relayed vehicle is a waste of time if when you push the button the dash light goes on. And if the dash light does not go on the 4th gear switch is usually at fault if not the wires in the shift column from the button.

If your OD off problme is with an automatic, you might want to examine aga9in the contacts on the back of the circuit board with a stronger magnifying glass. The first time the poor connection might not have been evident and it got missed or not hot enough for good reflow of the solder.

Duane