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So, it has been finally phased out of service. Do you have any official sources about this event ?

So, it has been finally phased out of service. Do you have any official sources about this event ?

Reverse works pretty much the same way it does in your road car (see ZF transmission above for example) - by locking one of the carriers onto the case. Only it has to be turned on on both sides here. BKP is essentially not very different from any automatic transmission - it's a planetary gearbox with 4 planetary gearsets and 6 wet clutches. The only two things it lacks to become a proper automatic transmission are torque converter and governor - walve box is already there.
It's small size is mostly the consequence of each gearbox transmitting only the half of the summary power output. This, plus the fact that there is no steering mechanism.

I must also add that T-80 wasn't very different from T-64 and T-72 in this department. It also didn't have neither any differentials, nor steering. It's BKPs were slightly smaller with 3 gearsets instead of 4 (it had 4 ranges instead of 7). Probably along with the fact that gas turbine doesn't have many auxiliaries reciprocating engines require and occupies less space, this was the motivation behind the idea to equip T-80 with hydrostatic ivt steering. The system was developed (see schematic below), tested, but never went into production.

There were two types of power train for GTD-1250 equipped T-80s. First - for domestic use, and it wasn't different from any other version of T-80 (with no steering, see below). And the second one (posted above) was marketed for international customers.

Regardless of the choice of steering, BKPs on all T-80 tanks were different from those used on T-64 and T-72.

GTD-1250 transmission on tanks in Russian inventory is not different from GTD-1000 transmission. At least not fundamentally, probably the ranges are slightly different, I'm not entirely sure about that. Again, I should strees it that transmission with hydrostatic steering was never produced - Russian military was not interested in it, and no foreign customers have been found.

Neutral steer is possible with BKP mechanically wise, but iirc control system does not have this option.

Oplot has pretty much the same transmission setup as T-64, but with external gearset for reverse, so that the vehicle can move backwards on any range.
There is also a bizzare version with hydrostatic steering, that doesn't have any links between BKPs other than engine's crankshaft. It has two IVTs each paralleled to the mechanical part of respective BKP so that reduction can be made continuously without shifting down. But it is forever in development and was never produced. No schematics available.

Pereh ATGM carrier was finally laid to rest yesterday (21/02/17) in a ceremony held by both active duty servicemen and reservists. 
Proper replacement will be found.

French APFSDS :

Left to right, second row : OFL 120 F2, BSCC 120 F1, 140 mm APFSDS,  OFL 105 F2, OFL 105 F1 or G2, OFL 90 F1, OFL 90 F2, OCC 90 62
Left to right, front row : OFL 120 F1, OECC 120 F1,  two non-identified arrows

French APFSDS :

Left to right, second row : OFL 120 F2, BSCC 120 F1, 140 mm APFSDS,  OFL 105 F2, OFL 105 F1 or G2, OFL 90 F1, OFL 90 F2, OCC 90 62
Left to right, front row : OFL 120 F1, OECC 120 F1,  two non-identified arrows

R. P. Hunnicutt, Abrams: A History of the American Main Battle Tank, Vol. 2

Quantified data about this 105 mm smoothbore gun and its APFSDS are shown in the following table summarising the trilateral trials :

AMX-30 M693 20mm autocannon superelevation (-8° to +40°) :
 

AMX-30 M693 20mm autocannon superelevation (-8° to +40°) :