You have an engine that transfers mechanical energy via a drive shaft and a transmission and a differential to the wheels.
The transmission allows you to use gearing so that you can go slow with the engine turning fast but the wheels go round slower and you can go fast with a high gear where the engine goes and the wheels go faster. You can also choose a reverse gear where the engine goes the same way it always goes but the wheels go backwards.
The differential is for when you turn. If you think about it as you turn, the wheels on the inside of the turn do not travel as far as the wheels on the outside of the turn. If both wheels are powered that means both wheels will be turning at the same rate so the inner wheels will spin because they are forced to turn the same amount as the wheels on the outside of the turn.
A differential simply allows the outer wheels to turn more and the inner wheels to turn less.
Edit: you would also add the complication of a gear box too, which becomes a little redundant for an electric drive vehicle.
For this new tank rip out the engine, the drive shaft, the transmission, and the diff. On each wheel you put a powerful electric motor to turn the wheel and drive the vehicle forward or backward.
Now to power this vehicle you need a reliable power source and the simplest way to get that is to take a small powerful gas turbine engine and connect it to another electric motor. The gas turbine doesn't need a transmission or gears or anything, just a direct connection to an electric motor. When you put an electric current through an electric motor it spins a shaft that you can put a wheel or propeller or whatever on. If you attach a gas turbine motor to the shaft and use the gas turbine motor to spin the shaft on an electric motor it becomes a dynamo that generates electricity. This electricity can be directly wired to a capacitor bank and a battery bank to store electrical charge and it can also be sent directly to the electric motors on the wheels to move the vehicle.
The only connection between the power pack (which is the gas turbine and electric generator) is electrical cables so you can put the power pack in the front, the middle, or the rear of the vehicle.
You could mount it in the roof or the floor or a turret position if you wanted... gas turbines can be quite compact things.
Because there is no mechanical connection to the wheels the gas turbine can be kept at an energy efficent rpm which greatly improves fuel efficiency.
Most hydraulic systems in the tank could be replaced with electric.
The potential for electric armour, and even plasma guns suddenly becomes much more viable. Very simply a plasma gun replaces the solid propellent with a much hotter material that offers the potential enormous boost in muzzle velocities.
The propellent could be a liquid made up of two or more components that might be poisonous separately but not flammable. You could store these liquids separately in the turret so there is little chance they will contribute to a fire (because they need to be mixed first). Squirt an amount of each fluid into the barrel behind a round and then zap it with an enormous charge of electricity to turn it into a plasma. Different rounds could have different charges depending on the weight of the round and the velocity required. A particular target might warrant a higher propellent charge, whereas most shots might even need a reduced charge which should extend the barrel life.
The safety of moving such a dangerous thing as ammo propellent and separating it out into two non flammable materials would greatly improve safety for operations and for reloading the tank. An RPG hit on such a tank would not even cause a fire.
Should also add that especially with wheeled vehicles if you drive up a hill you are using electrical power... when you get to the top of the hill and start down the other side, not only are you not using electrical power to go down, you actually generate power because your momentum and the down slope will allow you to stop supplying electricity to the electric motors to keep driving you forward. If the slope is steep enough you might be able to maintain speed by no sending any power to the electric motors... and an electric motor with its drive shaft spinning is a dynamo or electric generator adding power to your capacitors/batteries.
The wheels can have brakes fitted or you can use electrical power for the equivelent of engine braking.
An enormous benefit will be lack of noise... for a stealth approach turn off the gas turbine and use batteries to sneak around at night. A gas turbine is actually much quieter than a diesel engine anyway. Its main faults are it generates a lot of heat, and it uses much more fuel than a diesel because it lacks torque and compensates with rpm. This compensation is bad for fuel efficiency.
Eliminating the mechanical stress of acceleration on the gas turbine however and just using it for power generation means it can be made much more efficient. Also increasing power of a gas turbine will be much easier than increasing the power of a diesel.
An example would be the 11,500hp gas turbine in the Mi-26 could make a super tank power plant with lasers and defence shields to make luke skywalker cry. An 11,500hp diesel would need a ship to carry it.