The differentials in transaxles are constructed like and perform the same function as those found on rear-wheel-drive vehicles. Planetary final drive assemblies should be inspected for chipping and wear. Use an inch-pound torque wrench to check bearing preload.
Check ring gear backlash with a dial indicator. Always compare readings with manufacturer specifications. The collapsible pinion shaft spacer can only be crushed once and can not be reused if the pinion nut has been backed off or removed.
These gears are often colored blue from the manufacturer but turn blue/black from excessive heat.
Some transaxles use a chain and sprockets to drive the transfer gear. These chains are checked for play or slack by deflecting the chain up using a screwdriver and then marking the case and then moving the chain down and marking the case again. The sum of the two is the total amount of chain slack. There's little deflection in a good chain. Some transaxles use transfer gears instead of drive chains to achieve the same results; transfer of power from the output shaft to the transfer shaft.