50W if you're going synthetic (recommended), 80W if you're going mineral.
On all Eaton-Fuller transmissions, the fill plug is on the left side of the transmission. You insert the drive end of a 1/2" socket into it, and turn it counterclockwise to unthread it. That's where the transmission oil goes. Eaton-Fuller recommends you use either 50W synthetic, or 80W if you're going with mineral oil.
No, 10 speed does not convert over. You would need to get a truck with either a 13 speed, or a 9C transmission (which is convertible).
Heavier weight oil might work in warm climates but I wouldn't put it in north of Texas. Eaton specs 50 wt. synthetic in their 18 speeds.
No you cannot change a 13 to a 18 speed, however you can change a 18 speed to a 13 speed just by changing the shift knob.
I've never heard of an Eaton Fuller 12 speed, nor am I able to find any references to one via Google. I've driven Eaton Fuller 8LL, 9 speed, 10 speed, 13 speed, and 18 speed transmissions - could you be thinking of one of these? IIRC, Volvo marketed a proprietary 12 speed transmission, and Meritor offered a 12 speed automatic, but not Eaton Fuller.
Keep rpm between 1400 to 1600
No you can not, it is a different transmission. The 18 speed has a splitter for the lower range as well as high range.
You'd be in the 18,000 lb. range.
Google images. If you want the sticker, any truck dealership will carry it.
Alfred Fuller was born on January 13, 1885.
Alfred Fuller was born on January 13, 1885.