hey, I'm a generalist not a expert wink my thought would be that the drawing is from the assembly manual, and if it was ever used in the vehicle [I've never seen it in any truck] it would have been as a tag near the jack, or as a decal, pasted to the gas tank

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics