Just from investigating other threads about Excavators and their symptoms... At first I thought it might be the Hydraulic Pump, so I bought a new one (small fortune), but then didn't install it yet, because it grabs and digs so well, I figured it probably wasn't the pump....it goes fast enough with both tracks moving in the same direction and in second gear, its do-able...... and of course on pavement or the like , it'll spin like a top (metal tracks).....but get me in any loose soil ,rocks,mud etc etc...it won't spin to save my life, totally bogs down...to zero value, I have tightened/loosened tracks, I have changed out the lube in the tracks.... anyway...what do you think it could be...besides that ;-)