The battery was dead as a doornail, having burned 4500mAH or 430mAh/mile.  It carried the speaker & camera.  There were some hills, but it never had such short range, before.  The left pushrod was shortened by 1 turn to make it toe out more.  The right tire seemed worn in the center.  The steering is bulletproof in this configuration.  That leaves transmission overhaul.  Considering how it gradually lost efficiency after the last transmission overhaul, with no significant changes, the transmission is the leading suspect.  

The outside of the mane gears have been soaked, but there was no way into the differential or 1 inner bushing.  Overhauling it requires tearing down the entire vehicle.

Not sure understanding this much detail of every anomaly would make any difference before ordering a new vehicle.  There are many finer points with a new vehicle which are unsolved, like where to mount the batteries, how much more power it'll take to move such a large vehicle, what kind of motor would be most efficient.  Maybe the solution is to keep the lunchbox around for short range & small payloads while having a 3rd vehicle for camera mounting, long distances, & large payloads.