The Parts Difference Between Upper-Quadrant / Lower-Quadrant Headlights Is ...

Nothing more than the positioning of the existing OEM parts.

Referencing the M39-series 5-Ton gassers (M139, M51, M52, M54, M62 etc) , there are early-mid 1950's online gov't pictures featuring new gassers with upper-quadrant headlights.. This was quite surprising to me since I had previously believed gasser 5-Tons (and gasser deuces) were all originally lower-quadrant.. Throughout the 1960s while watching long convoys pass thru town, and during my own service time within the following 3 decades, all Deuce and 5-Ton gassers were lower-quadrant .. Apparently that was not always the case, since now seeing those old pictures...

I had also previously believed the upper positioning was done for visual uniformity after the advent of the A1's and A2's whenever a gasser got rebuilt into a multifuel A2.. But that is also incorrect .. Not all gassers nor all gasser/multifuel conversions got their quadrants flipped during their time in the inventory regardless of what I had seen during my own enlistment..

Why there was ever a difference in positioning is beyond my pay grade although I usually had noticed an improvement in Blackout Drive illumination (brightness) with upper-quadrant headlight positioning although the light did not spread out as far as the high ones on lower-quadrant trucks..

So here's the skinny :

Right-hand (passenger)

Lower Quadrant: Note the spacing of the upper/lower openings, and the removable crossbar is flipped upwards
Upper Quadrant: Note different spacing of the upper/lower openings, and the removable crossbar is flipped downwards



Left-hand (driver)

Lower Quadrant: Note the spacing of the upper/lower openings, and the removable crossbar is flipped upwards
Upper Quadrant: Note different spacing of the upper/lower openings, and the removable crossbar is flipped downwards



To perform the change, all you have to do is remove the 6 bolts from each of the two rectangular mounting boxes and take them out of the truck .. Then remove the 4 bolts from the B/O Drive lamp mount and also the Headlamp boxes , Invert the rectangular mounting boxes and reinstall what you removed .. Then put the two sets back in the truck.. Also, you will need to remove and rotate (flip up or down) the two horizontal crossbars.

This topic has been covered here, before: All W/Winch trucks have their HL in the upper position.
Otherwise the (raised & extended) bumper would project a shadow on the ground, not far ahead.

Early Non-winch trucks had them low.

gringeltaube said:

This topic has been covered here, before: All W/Winch trucks have their HL in the upper position.
Otherwise the (raised & extended) bumper would project a shadow on the ground, not far ahead.

Early Non-winch trucks had them low.

headlight placement

Is there a reason for the different placement of headlights on deuces and 5 tons some are at the top with the horn and black out light below? While others are below the horn and black out light.

www.steelsoldiers.com

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I was just gonna state this.

Low headlight trucks can have them flipped to high headlight position. The crossbars get swapped one side to the other and turned over (because of the way they are bent).
Some factory high headlight trucks can be flipped to low, but most can't.

If you pause between flippings, the truck looks really odd! I just didn't like the headlights low on my M185.

Cheers

The Two Guilty Subjects of this discussion !

msgjd said:

The Two Guilty Subjects of this discussion !

View attachment 928527

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Bwahahahahaha

gringeltaube said:

This topic has been covered here, before: All W/Winch trucks have their HL in the upper position.
Otherwise the (raised & extended) bumper would project a shadow on the ground, not far ahead.

Early Non-winch trucks had them low.

headlight placement

Is there a reason for the different placement of headlights on deuces and 5 tons some are at the top with the horn and black out light below? While others are below the horn and black out light.

www.steelsoldiers.com

Click to expand...

While digging thru some old manuals in my M109's desk drawer the other day i came across a 1965 M44-series deuce manual that discussed differences between the gassers and dash-A1 multifuel trucks .. Among the list was a mention about headlamp quadrant position , gasser non-winch trucks vs gasser winch trucks and multifuels..

You , Will Wagner, and others are 1000% correct ! .. The verbage does not appear in the later manuals i have , including M39-series 5T manuals