Flail mower gearbox oil?

[biffo]

Have just bought a used Kubota flail mower and will service it before using for the first time.

The recommended gearbox oil is SAE 90 oil. I'm a big fan of synthetic oil and have Mobil 1 75W-90 gear oil around for other uses, and I'm thinking of using this in the flail gearbox.

Is this a good idea, any opinions out there?

 

[Heavyduty]

It should be O.K. Running regular 90w is also fine as long as you change everyother year. Condinsation will mix in with oil and dilute it.

 

[DieselPower]

The 75W/90 will work just fine.

 

[Soundguy]

I'd flush as much of the old oil out as posible.. perhaps add a cup of diesel to eah gearbox, agitate.. then let drip-drain for an hour... then add the good stuff.

soundguy