04 F550 dump body fluid?

[hisilver]

This truck does HEAVY towing. Pulls big tractors while loaded with 4 to 5 tons of whatever in the bed. No owners manual. Rear diff has not been changed since new (40K miles). What weight do i use and how much? 75w140 or is there something heavier? Even when unloaded it has to carry a big steel 8x12 dump body on it. Thanks.

 

[DieselTech]

Youll want 75-140 syn such as amsoil sever gear redline or mobil 1. Also add 1 bottle of limited slip additive 4oz.
should be a Dana 135 in it

 

[hisilver]

Cool, thanks

 

[artificialist]

Originally Posted By: DieselTech
Youll want 75-140 syn such as amsoil sever gear redline or mobil 1. Also add 1 bottle of limited slip additive 4oz.
should be a Dana 135 in it

+1.

And perhaps the dump body has hydraulic fluid in it, and that should replaced occasionally as well.