We have recently bought a TL01 – Off Road

We are using the following setup:
19 Pinion Gear, 540 Tamiya moter, Standard Tamiya Speed Controller. The front & back diffs are locked

We have been struggling with the electronic setup.

In one month we burned two motors out and the speed controller.

What should be the most reliable setup, if we play on gravel heaps that varies in heights up to 2 meters?

Locking the diffs will put extra strain on the drivetrain, and therefore the motor. A standard motor will struggle in loose gravel. The teu-101bk esc can easily handle a Tamiya Sport Tuned motor, so throw that in. If you want more drive to the wheels in the gravel, put the bevel gears in the rear, and a ball diff in the front. t can take either the Manta Ray diff, or another one I can't remembe off-hand.