The Russians use a different transmission and gearing. Both the engine and transmission can be replaced quickly under battlefield conditions by the 3 man crew - which is something no western tank can match despite the other specs.
The gas turbine engine of the M-1 Abrams is smaller and lighter than a comparable diesel motor. The transmission is part of the power pack that can be replaced in as little as one hour. Three men are NOT going to move a large armored vehicle engine without some kind of mechanical device. There are videos online showing US Army personnel using a recovery vehicle in the field for that purpose. You might want to check your sources.