Another document indicating that IS reliability problems were not an isolated incident:Art wrote: ↑21 Nov 2017 16:50In a report submitted on 7 July 1944 technical officer of the 5 GTA noted that the army had to make marches on marshy and forested terrain, partly with sandy soil. "On those difficult roads heavy tanks and self-propelled guns of the 14 Guards Tank Regiment and 376 Guards Self-Propelled Regiment completely expended their maintenance resource and 70-80% of self-propelled guns and KV-2 (sic!) tanks are now in need of medium repair".
Some factory defects were discovered such as a flywheel having a faulty binding to a crankshaft or planetary steering mechanism's tendency to break down due to dust and sand. Special commissions from the Red Army's Tank Directorate and Commissariat for Tank Industry were called to investigate them.
An order of the Marshall Fedorenko from 27 July 1944 stated that in the first half of July the 1 Baltic Front had 46 heavy tanks and SP gun broken down due to technical factors. The reasons were said to be faulty maintenance and operations of vehicles: the air filters were not correctly assembled and installed and were not cleaned with sufficient periodicity, nonstandard oil was used for lubrication. It was also said that some unit commanders ignored recommendations of technical officers and didn't allocate sufficient time for tank maintenance.
The same place and time generally where the 5 Guards Tank Army was operating.