Vintage Tomy Big Loader Construction 1977 Set 5001 Complete NON-WORKING Read

Vintage Tomy Big Loader Construction 1977 Set 5001 Complete NON-WORKING Read. This is a very nice playset with all the parts, original box, and instruction sheet. Unfortunately, the mechanized chassis doesn't work. The batteries were left in and corroded. I opened it up and cleaned it but the wires and part of the battery terminal were corroded away and my soldering skills are not up to this. Also, a gear fell out and I'm not sure where it goes. Everything else--box, track, truck tops--are in very good condition. Please see pictures.