Grease for ABEC3 bearings

[Ducati996]

I have a 52" commercial mower and have replaced the blade spindle bearings 2 or 3 times in the last 15 years and the bearings have been greased using a Moly fortified grease.
The bearings are 6305 zz shielded bearings 2 per spindle.
The grade of bearing I used for the previous replacements is unknown but the bearings I just purchased are ABEC 3.
I know there are very specific recommendations for ball bearings and in the past Moly was not recommended but to keep things simple I use Moly fortified grease for all my vehicles and equipment including u-joints.
My 1990 CTD pickup has 250k with the original u-joints so I know this grease works well in u-joints and wheel bearings.
My question is will a Moly grease work ok in my new ABEC 3 spindle bearings or should I get another grease gun??

Thanks
996

 

[Tempest]

Are the bearings not pre lubricated from the factory?

 

[Ducati996]

There was no corrosion or contamination on or in the bearings, I do not wash the deck and they are greased in spring and mid season and I only use quality lubricants. This mower is not used commercially, is 15 years old with 506 hours on it and garaged.
My thoughts are that the spindle assembly is a bit under engineered for the use/abuse it sees.
It is not uncommon to hit rocks, roots and ground it on uneven ground. This puts extreme loads on bearings that were not designed to take heavy thrust loads. Tapered rollers bearings would be ideal in this application.
So back to the question would a Moly grease harm a precision ABEC 3 bearing???

Thanks
996

 

[Ducati996]

I never did inspect the old bearings to determine why they failed but I will open these up and take some photos so we can determine the failure mode.

Thanks
996