80 w 90 you should eat cake
if your referring to the Roberts diff lock its manifold Vacuum created by the engine and this works in a piston arrangement to lock the diffs
No it is not it is rear wheel drive the way it should be!
Should be
Around 90 weight gear oil. Check owners manual for viscosity but that should be close or a better auto parts store can look it up for you. 90 is pretty much standard for a lot of diffs.
It should already be four wheel drive.
they should the four wheel drive should not matter
you should check with the company. then you should file a law suit if you have 2 wheel drive
The year, make and model info would help.
Whatever the speed limit is.
Yes, an all wheel drive should be able to drive just fine on beach sand. All wheel drive will also drive fine on snow, damp roads, and other terrain.
Check the sticker under the hood near the center of the vehicle, it should show "all wheel drive" if it is all wheel drive, or look under the vehicle to see front axels and wheel drive shafts and rear drive shaft and rear end "pumpkin"
No. A "all wheel drive" is all the time four wheel drive. A 4x4 or 4-wheel drive can be set to drive in two wheel drive or four wheel drive.