Suzuki change gear oil at first 5000kms. Recommended one is GL4 75W-90. Make sure that Suzuki use multi grede oil ( personally I observed that they use GL4 90W only which is very thick, that's why I replaced with other good brand gear oil after using for only 5000kms)
Exact quantity is 2.3L and most of Suzuki dealership use only 2L. So make sure that fill it to required quantity. It may cost you 3rd bottle.