Yes, you can change a Massey Ferguson TE20 to power steering. The process requires purchasing a conversion kit specifically designed for the model, which contains all of the necessary components and instructions. The kit typically includes a power steering gearbox, a gearbox mount, a steering column adapter, and necessary mounting hardware. Depending on the type of kit, different other components may be necessary. Installation of the kit and necessary components is a fairly straightforward process, although professional assistance may be necessary for some steps.