barring over a 3406E cat engine.

There is a place on the rear structure to put the engine turning tool or a 1/2 inch drive ratchet and a shallow 15/16 socket on one of the balancer bolts. Standing on driver side you want to pull it to you or tighten the bolt

 

Use a pipe wrench on the balancer. You'll surely see marks where everyone else has.

 

Don’t be surprised if it needs new batteries, I’ve been where you are, charge batteries for a couple days, hit starter and just clicks, clean all connections, charge another day, same result. Switch out 3 brand new batteries, hit starter and it fires right off.

 

That's why you test them, coulda saved yourself 2 days

 

Well, the boss man said to bring back to life with the charger first.

 

Could be a hairline crack of the filter housing.
Could also be, possibly there is two gaskets? Maybe filter was changed, but the gasket stayed behind tucked into the grove that the gasket goes up into? (depending on the style of filter housing)

 

96 t680?!