The M3 Lee/Grant (there were two variants) is a truly strange-looking vehicle. It's so asymmetrical, utterly impractical and just steampunk overall, that one has a hard time believing such a thing could ever see wartime service.
It was truly an interim design, a placeholder for a better vehicle that would displace it. It was also the price the Western Allies paid for completely neglecting tank design during the 1930s and then fumbling wartime development. The British in particular made a botch of their tank forces and by 1942 were still consistently outclassed by better-performing German machines.
By the way, I'm not falling into the traditional trap of assuming that because something looks better on paper, or is more beloved by civilian historians that it is in fact objectively superior. British tanks had some good points, but they were few and far between. German tanks tended to be (like everything else they made) overly complex, filled with fiddly gadgets whose breakdowns hampered their reliability. The British managed to be worse.
The US knew it had a good design with the M4 Sherman, but ramping up production took time, so they cranked out the M3, which was tall, spacious and bizarre. The Russians (who knew good tanks when they saw them) derided it as a "coffin for seven brothers" (the number being the amount of crew).
Sahara prominently features an M3 because that's what was in use when the film was being made. You see them climb all over one, open up the engine compartment, start it, re-start it. Lots of detail for the true tread-head.
The movie itself is a wonderful piece of wartime propaganda, chock full of slogans and stereotypes to get the home front fired up. The setting (as the title implies) is North Africa and the time is 1942. The prologue tells us that a small detachment of American GIs have been sent to learn the art of desert warfare.
Almost immediately we begin the classic Assembling The Heroes. First we have Bogart, a career American soldier and senior NCO. He's backed up by a Texan and a New Yorker. His depleted crew is in retreat along with the rest of the British 8th Army, and soon they will add a smattering of Commonwealth troops picked up at a field hospital: English, Australian, Irish, South African. They also find a Free French soldier and subsequently add a Sudanese sergeant (serving with the British) and his Italian prisoner of war. Rounding out the core cast is a downed German aviator who plays the Evil Nazi role to the hilt.
With the exception of Luftwaffe pilot (who is a dead ringer for David Bowie), these bedraggled warriors will learn to set aside their differences in the name of fighting the common foe. There's a nice scene where the Italian explains that Mussolini duped the Italian people, but they still kept their souls. Nazis have none. A fight naturally follows.
This sounds all by-the-numbers and cynical, but the performances are really good and done with considerable sensitivity. The presence of a black man in the Allied cast is noteworthy, and given that the US Army was racially segregated at the time, would have been a bit fraught, so introducing the Sudanese soldier is a wise decision, being both plausible and interesting. He clearly not only can appeal to American blacks but also British Colonial troops. He's also a Muslim, and he is (naturally) the most experienced in dealing with desert survival, being a third-generation soldier for the Crown.
With the war still in its early stages, there aren't a lot of successes to celebrate, and so the story of the film is a stubborn (and seemingly useless) stand against all odds, because that's all the Allies had done to that point.
Lots of ignorant people assume that propaganda movies don't have any friendly casualties, but that's absolutely not the case. Our team of heroes gets all but wiped out (starting with a very young Lloyd Bridges playing a Brit), but they do so in a noble cause.
The Germans are uniformly portrayed as vicious and treacherous, which may seem cartoonish, but the Nazis earned every bit of it.
But let's get back to the tank! Okay, not just the tank, but the equipment. Because this made in wartime, authentic gear is in short supply, so both Allied and German gear is recycled from World War I. The Commonwealth troops are using SMLE-pattern rifles, not the Rifle No. 1 Mk IV which was then in current use. The Germans are likewise using WW I surplus, particularly their helmets, which still sport the lugs for the extra (and rarely worn) front plate used in trench fighting.
Oh, and the Germans don't have any MG 42s (or even MG34s), but are using Maxim guns. I wonder if they raided the prop department from All Quiet on the Western Front?
Usually when the gear is wrong, that's a sign of sloppy prop work, but not here.
One final note that I can't leave out: when the Free French soldier comes face to face with the Italian, he wants to kill him because he's been fighting "that type" since 1936. When asked how that could be (the European war didn't start until 1939) he mentions Spain.
So here's yet another example of Hollywood linking the Republican cause in Spain with the Allies of World War II.