Question about the width of front and rear differentials…

[Richard]

They are the same for trucks and Blazers. I got this response with a search.

The wider front axle on older 4WD trucks is primarily a mechanical design necessity, not a performance enhancement for traction or handling.

Clearance for steering: The front axle must be wider to allow the front wheels to turn without interference from the frame, springs, or steering components. This is especially critical with solid front axles and large tires.
Shared rear axle design: Manufacturers often used the same rear axle housing for both 2WD and 4WD models. The front had to be wider to accommodate steering knuckles and differential clearance, while the rear remained narrower for packaging and cost efficiency.
Tire rotation and spares: A consistent front-to-rear track width (or near it) allows for full tire rotation and use of a single spare, simplifying maintenance.
While some claim benefits like improved stability, reduced rut-following, or Ackermann optimization, these are secondary or misconceptions. The core reason is mechanical packaging — the front end simply needs more width to function.

What I have always believed.