Got one of those 900s, best thing you can do sell it to another sucker, pure junk. Mine was down two months last year and broke again after one mowing. It’s not worth changing the oil garbage. This machine was sold with so many problems. The 700 series was a great machine. Do not over grease the shaft to much 3 pumps every every 50 hours, it’s a sealed bearing you will blow the seal on it!
I've had mine four years and no trouble at all. I have no idea why you are having problems. I owned a 727 for 14 years and traded up to the 932 g2, glad I did it has much more power. I put a flail deck on the tractor and use it on the farm every week.
Stay away from this machine pure junk, I just mow my place and it was broke for 3 months last year and broke again after one cutting. Worth less mower stay away, My dealer will not sell one, go with a 700 series gas. Very underpowered machine with the Diesel!