The Dumper is by far the largest land-based vehicle in GTA San Andreas, generally based on large off-road dump trucks used in large-scale earth moving; the truck resembles a cross between a 1970s Caterpillar 773 (particularly the grille and cab) and more modern 773s. The Dumper is also only available in one color: Bluish gray, similar to the Dozer. The Dumper is similar to the Dump in GTA V.
The Dumper is a slow moving vehicle (with a top speed roughly similar to that of a Linerunner), but has the effects of the Monster truck. The "tipper" on the back can be raised up and down.
The default radio station in the vehicle is K-Rose.
There seems to be a glitch with the Dumper during one of the Quarry side-missions, where you have to transport explosive barrels to Verdant Meadows. Upon raising the tipper and dropping off the explosives, the player will occasionally be rewarded with a four-figure Double Insane Stunt Bonus.
The Dumper, along with the Monster, has the car crusher ability which allows the vehicle to be able to drive over traffic, rather than through it.
If a car hits the back of the Dumper, it will be set on fire or badly damaged. However, if the vehicle is directly on top of a car, sometimes the Dumper will get stuck on top of the car. The car will eventually explode and the Dumper will also explode too.