You have to machine brass gears to install the pershing gearboxes. You could use the stock gearboxes and connect them to the Tamiya DMD unit, which controls the throttle and other tank functions. The MFUnit controls the sound effects and is connected to the battle unit. My t34 has stock elevation and turret rotation devices and are hooked up to the Tamiya DMD and MF units. The speakers are 3watt 8ohm pairs, rectangular in shape. Tamiya machine gun unit and cannon flash unit. Daryl Turner did the mod for me for $250.00. There's a post on this forum. Just do a search of this name and t34 and you can read his own account of his work put into my tank.

Check Ebay and you may be able to find a Tamiya Pershing DMD and MF together for under $250.00 and the geardrives for under $80.00. If you want a sound unit that authentically replicates a real t34 down to the gear shift noise, check out Thomas Benedini products on his website, www.benedini.de. I have two of his sound units, the t34 and panzer III. His soununits are expensive and at the same time highly realistic. The 1/6 scale guys frequently use his devices. Good luck!