I seem to fight the same issue with this darn thing every year: Working on a really hot summer day causes the gasket between the TOM body and the rockshaft to blow out. Because this is also the gasket for the hydraulic fluid reservoir, it makes a terrible mess. When it happened this year, I parked the tractor and moved on to other projects which in hind sight was a mistake because the garden isn't tilled, the property I'm caretaker of isn't mowed, it is December in Michigan and I can't plow snow without it.
Maybe this will illustrate the design flaw I'm fighting:
I think the root of the problem is that there are no bolts across the bottom of the TOM/rockshaft because this is where it blows out every time. Due to the tight fit between the rear axle and belt drive pully, there is no way another fastener can be added. I've been fixing it with OEM gaskets and running OEM specified 10w hydraulic fluid; same as iso 32 spec light hydraulic fluid.
This time I'm determined to fix it once and for all. Clearly fixing it the right way isn't working so it's time to try something else. Before I reveal my plan and taint any ideas yous guys might have, I'd like to hear some of your options.