 I would for sure stick with 80-90 in the rear end. Hydraulic wouldn't be thick enbough to really "stick" to the gears when they're meshing, it would increase noise and wear in the drive train. As far as running synthetic in the engine, It may help, but you're still gonna have to chaneg the oil more often than most tracotrs because of the small oil pan, unless you have a fab shop add about 3" to the pan. I think that will add another 1 1/2 gallons or so to the capacity, which will almost double it's current capacity. I change the oil in our 1855 about every 50 hours. It' does all of the really heavy work so it burns oil and has extra deposits in it from that and the extra heat load placed on it. I know some guys change it at 100 hours, some at 50, and some of both crowds run synthetic in the engine and swear it adds 100,000 hours to the life of the engine. For me, more frequent oil changes with a good 15W-40 deisel rated oil is good enough. For the price of synthetic you better have some deep pockets, espescially if it burns any. Donovan from Wisconsin
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