changing diff fluid

[Darektylka]

what type of oil is everyone using to flush there diffs? how many quarts ?

[ramsdell_]

I need to know which rear diff you have to let you know which fluid. For the front you need a GL-5 rated oil. AMSOIL offers a number of different options for this. I would recommend Severe Gear EP 75W-90.

Here is the capacities:

Rear Differential, With 10.50 RingGear..........3.5 quarts
Rear Differential, With Dana M80..........4.25 quarts
Rear Differential, With 10.25 RingGear..........3.5 quarts
Front Differential..........3 quarts

[Harley350]

How do we find out which rear we have?

[JSchuricht]

98 or older has the 10.25
99+ has a 10.5
99+ DRW has the Dana 80