Dodge 2015 RAM Owner's Manual page 326

324 MAINTAINING YOUR VEHICLE
Component
Front and Rear Axle Fluid (2500/3500)
Front and Rear Axle Fluid (4500/5500)
Clutch Linkage
Manual Transmission (G-56) – If Equipped
Fluid, Lubricant, or Genuine Part
We recommend you use Synthetic, GL-5 SAE 75W-85.
Limited slip additive is not required for Limited-Slip
Rear Axles.
We recommend you use Synthetic, GL-5 SAE 75W-90.
Limited slip additive is not required for Limited-Slip
Rear Axles.
We recommend you use MOPAR® Multi-Purpose
Grease, NLGI Grade 2 E.P. or equivalent.
We recommend you use MOPAR® ATF+4® Automatic
Transmission Fluid or equivalent licensed ATF+4®
product.