Rear Diff Code 45 - Do I need an additive

[ArmedMikeQ]

I looked on the door of my 04 Mercury Mountaineer Limited AWD and the axle code is 45.

Do I need the additive when replacing the rear or front diff fluid?

Thanks !

 

[PopRichie77]

No, only limited slip diffs need an additive. Limited slip codes are a letter and a number, yours is a 3.55 open diff.

 

[ArmedMikeQ]

ok good so I can use this in my front and rear diff?

Front:
http://www.lucasoil.com/products/display_products.sd?iid=43&catid=12&loc=show

Rear:
http://www.lucasoil.com/products/display_products.sd?iid=47&catid=12&loc=show&headTitle= - Lucas SAE 75w-90 Synthetic Gear Oil


The front calls for 80w-90

The rear calls for 75w-90

So I just want to go to autozone and get about 2 quarts each for front and back.

Thanks.